Our current 40' 5'er lives in Clarkston and gets its servicing done in Missoula so we have been this route multiple times in the last 24 months. Hwy has been lumpy in areas on the west side of Lolo however the state of ID DOT continues to work on it in the summer. As others have said, very scenic, very twisty on the west side as it follows the river next to the road. Nice rest area at the summit of Lolo Pass with restrooms and a visitors center. Huge parking lot with spaces for large RV's on the east side of the lot. Watch for moose on the east side once you get back down on the flats from descending the pass. There a couple nice cafe's to eat at on the west side down on the flats that we have enjoyed meals at and visited with the locals.
Depending on the time of year there can be tons of folks visiting the area in the spring when the snow melt swells the river making it popular with kyakers and other water enthusiests trying not to drown in the hughe swells and white water areas of the river. So they can be everywhere parking where they can on the edge of the road. Most use pull outs but not all.
If you're not in a hurry there is a nice walking trail out behind the Lolo Pass summit visitor center that makes a nice relaxing walk to limber up from sitting while driving. We did it one trip. Also on one trip it was snowing and folks were unloading and departing on their snowmobiles to head out on a trail that departs from the summit parking lot.
I can say with certainty the road on the east side of the summit (state boarder) is much better then the west side of Hwy 12. But all in all it's an enoyable drive especially if the weather is nice. One trip there was an active wildfire on the flats of the east side. Hwy had been closed however the fire had burned through and the Hwy had reopened to the public but there was lots of fire related vehicle traffic for about 15 miles and restricted speed was 35 mph.
George
