US 95 Spokane Wa. to Boise Id.

I driven both roads a lot. The Boise to Tri-Cities to Spokane is the fastest all freeway all boring. 95 is slower but much more to see some areas of hills and tight corners but no biggie. You can avoid the Lewiston grade by going through Moscow.

You can run it on Google maps/earth. I don't see the problem. It's a US highway, and plenty of trucks use it all the time. A bunch of it is 4 lane. So there's some hills -- big deal!

I used to live in Coeur d'Alene, ID, and would often use the majority of the route you're talking about. My length with toad is about 4' shorter than you. As long as you're not in a hurry I would highly recommend this route just for the scenery. The approach into Lewiston is a little tight, but I know you're a full timer and experienced driver so I don't think you'll have any trouble at all with it, and the view is worth the tight turns.

My biggest learning curve on the steep portions of that route was how to deal with the logging trucks. I don't have the power plant that you do, but I could easily find opportunities to pass them on their slow ascents. The problem I found is that they are very familiar with the highway and could handle the descents at a high rate of speed. Of course I wasn't descending anywhere near their speed, so consequently they would wind up with their front bumper a few feet from the back of my toad. I found there are some straight sections that you can pull slightly to the side of the highway, and they won't waste anytime getting around you.

It's a drive that should be on your bucket list to do at least once.;)

P.S. Every time I see your pictures, I have to chuckle at the "low rider" MH.

Dennis, tractor trailer rigs travel that route all the time. As others have stated, there is a large, fast drop into Lewiston, just heed the signs and you should not have any problems. Depending on time of the year, there is usually a breeze North and South of Moscow, which gives meaning to the "Amber waves of grain". It will be warm in the summer, just take it easy and enjoy!

US 195 to Lewiston then US 95 south to New Meadows and ID 55 to Boise would be my choice. great scenery!
Steep down grade just north of Lewiston on US 195 and another down grade near White Bird.

It is just as fast to head to tri city then over to Boise,
If we're me and that long, I would head tri city,then 84 to Boise.

It can be windy steap in places and slow a lot of the way. There is a long drop into Lewiston that ends in a 30 MPH hair pin turn. IMHO better route is due south out of Spokane thru Colfax. From Lewiston pick ip 95. Still has some narrow twists, but doable.