I would not generally want to take an RV on HWY 1 other than for a short part of the road, meaning stay somewhere near a fork that branches back to I-5. I've driven it on a car many times. It gets VERY foggy sometimes, and the fog can take days to lift. When I say very foggy, remember that mountain fog you once saw where you couldn't see more than 5 feet in front of you...
I guess if you do it in the summer and make sure no fog and no bad weather in general. Though the road in places itself is treacherous, too many curves. It will wear you out from the LONG curves. In some ways it is worse than driving on mountain roads, because the roads are made to where people go much faster.
I got worn out driving it from LA to Monterrey when I was 25 years old and in a sports car, much less driving an RV!
Also people are careless on that road, sometimes motorcycles by kids, other times tourists looking at the scenery instead of the road.
I'd camp not farther than 10-20 miles from the ALT route, because otherwise you will get stuck on the road driving for hours and hours in the fog.