Last I knew you could overnight there. It's been several years though. Babiemox on here would likely be in the know. I will send her a message and let her know you are asking.
Here are a couple of names and numbers to try when I googled fairboard members. Carolyn Pasha - Board chair 406-563-3848 Danielle Stevenson, Secretary 406-498-8639
If you are just traveling through and can stop 40 miles sooner contact the Montana Livestock Auction just off the interstate in Ramsey. Or if you can go another 30 miles past Deer Lodge here is the contact for the Drummond Rodeo Grounds. 500 Highway 1 South