Central Oregon to Bozeman then Tetons.

Last year Bozeman's Museum of the Rockies had a super cool exhibit on frogs - way cool - so imagine they'll have something super all the time. Assume you will be taking Rt 89 thru Big Sky and Gallatin Canyon - some nice campgrounds along the way. However, north of West Yellowstone is Rainbow Point and Baker's Hole cgs. You're on a lake with the former and a river for the latter. I know it isn't much of a drive to either so if you don't want to go straight thru to Teton NP, that would be my suggestion.

However, heading back, I suggest you look at the possibilities for Island Park, ID. In Jackson, WY head west on RT 22 (it becomes Rt 33 in ID) thru Driggs, ID (there is a sweet little Targhee NF campground named Teton Basin that backs up on Teton mountain range but I think your family might be too young just yet) and continue on to Island Park, ID. Buffalo is on the Buffalo River which is a super family float river plus there are some sites with electric, flush toilets, dump stations nearby and a lodge across the street that serves B/L/D. (Can you tell it's a personal favorite.) But truth be told, all the Forest Service campgrounds US 20 are nice. Mesa Falls is impressive and the trout near Big Springs campground, at the cabin, are too - nice daytrips. Continue north on 20 then 287 to I-90 and head home. (FYI: There is a fun private hot springs with a small campground in Norris, MT - just made for families and delicious pizza at Pit Stop Pizza in Ennis, MT. Ennis also has a fairly decent grocery store and about the only gas for miles.)

Welcome.

My first thought is that, if you haven't already, you may want to take a short weekend trip first to work some of the kinks out of the trailer and your camping system. I doubt you will have any problems finding great places to go here in Central Oregon.

As for campsites, you may want to look at this website for ideas.
If you like state park type camping, Three Island Crossing State Park, in Glenns Ferry Idaho would be a nice, cool, place to spend a night or two.

Have fun and safe travels,
Steve

Is the 3-1/2 into Dinosaurs? If so, go to the Museum of the Rockies while in Bozeman.

If Three-Island State Park (Idaho) is on your route I've always liked it. For more flexibility check www.rvparkreviews.com