I would be interested in both hwy 1 and hwy 101
You might spend a nice quiet evening on this forum on this topic. There has been quite a bit of discussion. California SR 1, the Pacific Coast Highway, is arguably the most scenic road in all of America between San Luis Obispo and Leggett. You will have no issues with the Class C as logging trucks, folks with fifth wheels and travel trailers and even Class A RV's ply this route. Just take you time and know where your coach's wheels are when going around a corner. Don't let fear keep you from this route segment of your trip. Try to go through San Francisco after the morning commute and before the afternoon commute or after hours in the evening. Bay Area traffic can be considerable.
US 101 is a four lane highway and often miles from the ocean. It does got through the Redwoods, but you will miss Big Sur, Bodega Bay, most of the lighthouses, and most of the ocean. Come this far, see what you want not what is on the interstate routes or a busy four lane arterial highway.