Looking for a Forest Service park in SW Montana

I think that the suggestion to camp at Clark Canyon Dam south of Dillon on I-15 would suit your needs the best. It's very handy being close to the freeway (but isn't noisy) and will give you some space and openess feeling!

Try The Ultimate US Public Campground Project. It contains locations and information on more than 18,400 public campgrounds.

Ted H.

Not sure when they close, but Swan Lake annex was great in August. They have large sites and clean pit toilets.

OOPS - missed the part about going to Utah so I deleted my bit about the Little belt mountains.

Divide Bridge will work. We use this at times with our 39' fiver and dually crew cab. There are two sections to the CG. The sites along the river are smaller but there is one we can get in, providing there is no one in it. There is a second section. Off to the right as you get to the CG. There is sites there that accommodate you. Another place is Clark Canyon Dam, 17 miles south of Dillon. Just off I-15. There is a free dry-camp area on the east side of the dam. Then on the west side is a rinky-dink FHU park that probably will be closed by the end of September. Also on the west side is two more free dry-camp areas. All these are operated by Bureau of Reclamation. We use Clark Canyon quite frequently.

There doesn't seem to be much that can accommodate a 40' MH, especially forest service, using this campground finder

Beaver Dam

Divide Bridge (BLM)

Ruby Creek BLM

U.S. Campgrounds.info has a pretty comprehensive listing of Fed/State/City&County parks. May be of help to you.

Sorry I don't have anything specific in mind but you can check out publiclands.org for all of the forest service (and other public) options.