The dogs needed to run after a long, long trip in the car. When we were on the outskirts of Parshall, ND, a small town in a sea of flat, cold, yellow crop stubble, we let them run. Here is the scene they stood overlooking, and a shot of them running off energy. Oddly, their legs were yellow after running in the stubble, and we never did figure out why.
Later the same trip we had a small disaster when we let the dogs run off leash through some trees and brush. They came back covered in extra teeny little burrs, smaller than I've ever seen before. They took literally over an hour to remove, and were a massive pain both for the dogs and for us. Running off leash in fields and parks was fine, but brush in ND is to be avoided at all costs!
Along the way we looked for other safe places for them to run off leash. In Billings, MT we found only one "dog park" and it was still marked for on leash pets only. People seemed to be observing that as well. Overall Billings didn't seem to be a dog town, though we finally found a place to let ours stretch their legs a little bit along a cold lake.
Bozeman, MT had a couple of dog parks and appeared to be a fairly dog friendly town overall. The dogs had a good time in the snow there, but did NOT want to get back in the car for another long and boring day of driving.
Once again I was glad for Holiday Inn's pet policies so we had options all along the road for where to stay. Kudos to all hotel owners willing to let pets participate in journeys rather than stay home.