Idaho is awesome. I just got back yesterday from another failed house hunting trip. I'm looking for specific house with acreage property in the area just North of the Treasure Valley that is apparently also very popular with other retirees and others like me, fleeing California. Last week two properties my realtor was going to set me up to see were sold sight unseen over the phone by some jackass Californians within a few hours of listing. Housing prices in most of the area around the Treasure Valley have jumped around 25% from last year.
The average Boise/Meridian/Eagle housing tract home is around $300K now. Idaho was the #1 growth state last year, and Meridian was the #1 city. It shows. Lots of extra traffic in that Meridian/Eagle/Boise area. If you don't mind a little commute, Caldwell, Nampa, Kuna, etc. areas still have some nice areas where you can get a place with even an acre or so for under $400K, and tract homes are mostly still available in the mid $200Ks.
On the positive side, if the Boise area is where you're looking, there are tons of outdoor activities (some of the best fishing in the area is on the Boise river right in town), really friendly people, great year round weather (at least for Idaho), great pubs and restaurants, state constitutional carry, super cheap hydro electricity, excellent medical facilities, the list goes on. Also Idaho, from what I've seen and based on everyone there I have spent time with, is very much "live and let live", from the Mormon South to the libertarian panhandle.
Bob mentioned a few other areas. That whole CDA and North area is really cool. I was in Bonner's Ferry last year and thought it was awesome. Real estate is still reasonable there too (not so much in CDA) but they do get some real Winters and they are just a bit of a drive (for me at least) to a lot of services. If I were 30, I'd seriously consider it. At 58, one of my criteria is being within an hour of major medical. If not for now, for 10-20 years from now, so I don't have to move again. I was actually first looking at the other areas Bob mentioned. Specifically Buhl to Hagerman, just North of Twin Falls. It ended up being just a little too desert-like for me, with some of the outdoor stuff I like to do being a bit too far away. Twin Falls has grown a lot though, and has most all the services anyone might want.
I've been looking North of the Treasure Valley, from New Plymouth through Emmett and to Horseshoe Bend. This is the property I really wanted that I lost to the jackass Californian with the phone:
https://www.zillow.com/homes/for_sale/89909830_zpid/87120-_lot/1_pnd/globalrelevanceex_sort/43.957389,-116.141632,43.954929,-116.146246_rect/17_zm/I would have been able to hop on my 4 wheeler, go down my driveway, hang a right, and ride into miles of BLM and National Forest land to shoot, hunt and goof around, and still be within 50 minutes of the Costco.