Highways 55, 95, and 12 are all good roads. I don't remember any driving challenges on Highway 55. I do remember that the northern part of 55 was very scenic. There is a big hill on 95 going into Grangerville. On the other side of Grangerville, you go back down the hill on highway 13. Highway 12 is fabulous. Nearly 100 miles of river road and twisties. Lolo Pass is on the east end but it isn't a bad pass.
This motorcycle movie shows a trip from US 12, up 13 towards Grangerville.
https://youtu.be/muO8wSmNx8I
This picture is on US 12.