I've only been east of Denver as a kid, but the west route looks pretty good. The only place I would change is south out of Boise.
Take the road from Mt Home to Eureka NV then hwy 50 west to Reno. A much nicer ride. Mt Home is less than 50 mi from Boise. Most all of these roads qualify as the long lonely road, but some are interesting because of terrain or small town. Mt Home to Eureka is a good one.
95, South of Boise, and I-80 to Reno are HOT!!! and BORING!!! Unless you like akaline desert.
Take the north route, you have marked, thru south Idaho. 84 is an abysmal interstate thru ID and UT.
Remember Canyon de Chelly, when you get to 4-corners area.