Seattle to McCall, Idaho

We drove that last August with our 40' MH towing the Jeep Liberty - coming from Yakima, WA. We took I-90 to 26 which was boring for us but an easy drive. Our main reason was to see the Palouse but all fields were plowed. Then you will have 95 into Lewiston which is a 7% downhill for 6 miles. It's very doable - many RVers drive it - but you should be prepared for 35-45 mph. Plan the night or two at Clarkston/Lewiston before tackling the rest of the drive. Hells Gate State Park was a very refreshing stop - lots of big shade trees on the river. We didn't have reservations but then we were there early in the week. Weekends require reservations. Then continuing on ID95 is White Bird Hill about 8 mi south of Grangeville. You'll have 8 miles of 7% grade downhill with 2-3 lanes. Again, you'll be going 35 mph. Those will be your biggies but again, doable. Just take your time. It's a beautiful drive!

Like Pauli said. Yes there are some big passes. Good news is that heading to McCall you'll be heading down the steep parts. If you've pulled Stevens Pass, you'll be just fine.

Sure - I90, but you already knew that.

WA26 and US12 get you over to Clarkston/Lewiston. US95 takes you south. Since Lewiston is the lowest point in Idaho, any way out involves a climb, essentially from Snake River level to a plateau 2000' higher.

Grangeville is on the plateau, Whitebird is back at Salmon River level. You climb again to New Meadows and McCall. McCall is relatively high (snow into May), but approaches are gentle.

I82/84 to Boise is also an option; with US95 or ID55 north to McCall. There's lots of weekend traffic from Boise to vacation homes around McCall.

I90 over to WA26 is a nice drive. Takes you straight across the state to Colfax. From there it is only a few miles to to 95 in Idaho.