I-15 to Idaho falls, then hwy 26 to swan valley, past Palisades res to Alpine, then Alpine to Jackson! Mostly flat and good roads! Not sure if there is any construction going on, probably!
We were just north of Salmon and down to Stanley last week and most everything is open! Lots of smoke but some clear days also! Was up to Island Park two weeks ago and the same applied! Fire restrictions in place so be aware!
We have the Cougar, love it but did have some issues the first few trips! Things came apart but I and dealer were able to get them fixed! Love the room when camping!
I would go to McCall, then head for Stanley, and possibly Island Park/West Yellowstone depending on the amount of time! There are a lot of campgrounds and areas to boondocks if you look! Good luck and have fun!