I've lived in Wyoming, Montana, and Idaho. As others have mentioned watch out for Montana taxes and they have high vehicle insurance rates.

Wyoming is alright but plenty of it has wind and you'll spend lots of travel time to get somewhere for shopping or essentials to an hub city.

Idaho? I wouldn't find Salmon the best choice.

Thompson Falls MT is nice and in Idaho anything south of Coeur d Alene down to Grangeville is nice. I really like where the Palouse area meets the woodlands and also I like the St Maries area and little settlements like Deary, Bovill, and Fernwood along the Whitepine scenic drive.