The thousands of cars that each day drive on Interstate 90 near the Porter Sculpture Park at Montrose are tiny compared to the 60-foot-tall bull head that dominates the nearby hillside.

An artist and entrepreneur who earns his living in the tourist trade, owner Wayne Porter said enormous and odd — both are in abundance here — are qualities that help him to bring in those travelers.

“The interstate is like a river,” said Porter, creator of the park and its more than 40 sculptures. “If there’s fish in a river, you’re more apt to get bites.”

Porter’s park is one many of the tourist locations — some niche, some kitsch and some more traditional —along Interstate 90. Smaller than more-publicized tourist destinations like Mount Rushmore or the Corn Palace, Porter and others say the success of their attractions is dependent upon their ability to lure tourists off the interstate as they motor toward their vacation destinations.

If Memorial Day is the official start to tourist season, then the week following is when owners of those attractions begin to get a read on the year. In South Dakota, the top tourist attractions are in the western part of the state, where tourist meccas like Mount Rushmore and the Badlands beckon to travelers.

In eastern and central South Dakota, the attractions rely on those same visitors, but owners and managers say they realize they have to work to get travelers off the roads and through the turnstiles.

The Daily Republic spent a day this week traveling Interstate 90, dropping in unannounced at some of the tourist sites between Montrose and Murdo. At each attraction, owners, employees and volunteers said it takes effort to catch the attention of travelers who may have entered the state only to see more West River destinations.

Elma Mohnen, a volunteer at the South Dakota Tractor Museum in Kimball, said the combination tractor and billboard located along the interstate near town often do the trick.

“I think a lot stop for the tractor and then discover something else,” she said.

Wanda Goodman, media and public relations manager for the state Office of Tourism, said marketing the uniqueness of a tourist spot — like many of the niche spots along I-90 — is the key to success.

“Stick with what you’ve got,” she suggests. “You’ve got a niche. In some ways, you have the upper hand because you are a specialized business.”

Since 2001, Porter said he’s been attracting all types of visitors at his sculpture park, from local farmers to international travelers.

He places brochures at rest stops throughout the state, but most of the interest in his outdoor sculpture park comes from media coverage, word-of-mouth and the collection of more than 40 sculptures that range from escaping goldfish to a giant hammer. All are located on the hills of the Vermillion River valley, very apparent to motorists.

Other sites along I-90 have taken a similar approach. Tucked amid the numerous Wall Drug signs that dominate the western South Dakota landscape are numerous billboards touting the Pioneer Auto Show, a longtime attraction in Murdo.

Its owner, Dave Giesler, said he spends $100,000 annually on advertising, ranging from magazine ads to billboards along the roadway.

“The signs,” he said, “are number one.”

At the sculpture park in Montrose, Porter this year already has had visitors from California, New York and the United Kingdom. But as gas prices continue to rise, he’s expecting to see a higher number of tourists from the more immediate area.

“Tourism is changing very rapidly,” Porter said. “There’s going to be a point when traveling people are going to travel locally.”

To Porter, the changes mean it’s time to focus on bringing something new to his park, even if it is a piece he admits “may never get done.”

To accompany the 60-foot bull that can be seen for miles, Porter is constructing an iron horse, 40 feet tall and 60 feet long. He’s not sure if the finished product will be the largest in the world, but he’s hoping it will provide an added bonus to those who tour his park.

“For tourism reasons, you want the biggest,” he said. “If I’m going to compete with the world’s largest ball of twine, I need a really big horse.”

Among the sites visited Wednesday by The Daily Republic:

South Dakota Tractor Museum, Kimball

As the sun shone this week in Kimball, Cletus and Elma Mohnen sat on a bench outside the South Dakota Tractor Museum in Kimball, awaiting the next visitor.

The museum was started by the late Ralph Bickner. Now in its seventh year of operation, it houses a collection of tractors, automobiles and antique household items that range from the commonly used to more exotic items, such as a dog-powered treadmill. Visitors also can tour a one-room schoolhouse complete with blackboard, desks and historically accurate school supplies.

The Mohnens are two of nearly 30 volunteers who give their time to operate the museum, which has no admission charge but accepts donations.

“We wouldn’t make a dime if we had to hire somebody,” Cletus Mohnen said.

The museum advertises at area rest stops. Travelers approaching Kimball from either direction can’t help but notice the billboard attached to a piece of antique machinery.

Although cars and motorcycles stop by on a regular basis, four to five tour buses stop by the museum each year, boosting visitation numbers.

Financing the museum is the biggest challenge, but donations stay steady enough to keep the museum going. The gift shop, filled with items ranging from historical tractor literature to dustpans made out of license plates, also provides some income.

If finances continue to hold strong, the Mohnens expect the museum to add another building to its location.

Mr. Mohnen said he was initially concerned with how gas prices would affect visitor numbers. So far, the stream of visitors has stayed steady enough assuage any fears.

“It’s not bad,” Cletus said.

Akta Lakota Museum and Cultural Center, Chamberlain

Tucked neatly into the north corner of Chamberlain, the Akta Lakota Museum and Cultural Center contains a complete history of the Lakota people. Being located on the campus of St. Joseph’s Indian School helps to draw curious visitors into the museum.

It’s that interest that brings a good number of people annually to the location, said David Baldwin, a teacher for the school who works at the museum in the summer.

Still, catching people on their way to Mount Rushmore and other western destinations is the key to success.

“That’s more what we see than anything else,” Baldwin said.

The museum distributes its own publication and actively works with state and local tourist organizations. Both the school and museum are solely funded by donations and almost every item in the circular museum has been donated or loaned.

When the tourism industry slows in the state, numbers do decline at the museum, Baldwin said. Still, a steady amount of national and international interest means attendance numbers never get dire.

“If it’s really low, we don’t really go down to their low,” Baldwin said. “We see people come here on purpose.”

Baldwin said the partnership between Chamberlain-Oacoma Area Chamber of Commerce and the museum helps keep numbers steady in the museum and the town.

“They use us as one of their primary sites,” Baldwin said. “They’re so excited about this place because they have people that come to them and ask ‘Where is that Akta Lakota Museum?’ ”

Model Car Museum, Mitchell

When Milo Sheldon received his first model car in 1949, he didn’t realize that it would start a collection that one day would fill a building and attract visitors from across the world.

“Every year I added a few and after 60 years, it amounted to something,” said Sheldon, owner of the Model Car Museum of Mitchell.

Even with 6,000 model cars, publicity is still the biggest challenge for Sheldon and his wife, Kathy, who rely heavily on a display at the Corn Palace to bring visitors to the museum.

The relationship with the Corn Palace is the main contributor to attracting car buffs to the museum, which charges admission to view a collection that varies from the classic to the unique, such as models of the Batmobile and the Trabant, the most common vehicle in what was once East Germany.

The museum averages 1,000 visitors a summer but so far, numbers have been below average, a decline Sheldon attributes to gas prices.

Even in its third year, Sheldon said he and his wife are still actively working on spreading the word about the car museum, advertising in rest stops and the occasional church directory.

“We’re relatively unknown,” Sheldon said.

Pioneer Auto Show and Prairie Town, Murdo

Call this collection of rare and unique automobiles and antiques what you will, said Pioneer Auto Show and Prairie Town owner Dave Geisler. Just don’t call it a museum.

“We are not a museum,” Geisler said as he stood outside his attraction in Murdo, which occupies nearly an entire city block. “We are an attraction. We are fun. We are an experience.”

Geisler, a former car salesman and coach, opened the show in 1954. Now, 54 years later, it contains buildings full of automobiles, tractors, motorcycles, toys, fossils and what Geilser touts as one of the top rock collections in the world.

Tourist season used to be 100 days long, but extended school years have cut into that span. In Murdo, the season has gotten off to a slow start, Geisler said, but he expects things to pick up as the number of interstate travelers increase.

Geisler expects 90 percent of this year’s visitors to be repeat customers, which he credits to an ever-rotating collection and friendly atmosphere that Geisler strives to provide.

“We work very hard on hospitality,” Geisler said. “People are pretty impressed with this.”

On Wednesday, the 35th day of a “round-robin trip” that had taken them from their homes in Oregon through Georgia and Canada, Jerry Walter and Barbara Clary found a sign advertising the show.

Sticking true to their motto of “Just look for signs on the road,” the couple spent Wednesday afternoon touring the Murdo attraction.

“It’s all about time or place,” Walter said. “Some days we drive 100 miles. Some days we drive 500 miles.”

Clary said she fell asleep in the car after considering the idea of visiting the show with Walter. When she woke up, they were parked in front of the building.

For the couple, the spontaneous vacation approach is the only way to go.

“We’ve been having a great time,” Clary said. “We’re footloose and fancy free.”