We are in Columbia Falls Kalispell area and are heading down toward Salt Lake City in a week. I have been researching camping and things to see. Here's what I found so far:
Idaho Falls ID - Snake River RV Park - mixed reviews, older park but ok.
Idaho Falls ID - Juniper Campground on Ririe Reservoir - 18 miles from Idaho Falls. Overnight Camping Fees:
$10.00 tent area and dry dock camping
$18.00 full hook ups ($2.00 discount for Idaho State Parks and Recreation Golden Age pass holders)
Shelley ID - North Bingham County Recreation Area. $20 water and electric.
In Ogden - Union Station & Museum - Utah State RR Museum - Hill Aerospace Museum. In Salt Lake City - Mormom Tabernacle Choir live broadcast. http://fans.musicandthespokenword.org/attend-a-live-broadcast/
We are also going to the Bonneville Salt Flats in Wendover NV. If you are a racing fan, you might want to do that. There is a KOA in Wendover.