The motorhome and bus map is a better guide for RVs in CA IMHO.
https://dot.ca.gov/programs/traffic-operations/45-buses-motorhomes/bus-mapIt shows the restricted roads for MHs over 40' so the OP is OK. I'm not aware of similar maps for long trailers, but it could be a heads up guide.
I've been on PCH many times in my 38' MH with a toad. It's a decent 2 lane highway. Check for road closures and fires especially south of Big Sur which seems to have it's share. Do not take 101 through SF, take 280 to 19th Ave or from 1 cross over to 19th Ave, stay in the right or center lane. PCH north of the Golden Gate is slow. As you approach Leggett there are several 15 MPH switch backs and they mean 15 MPH.