I would suggest hiking along the lost coast. It is absolutely gorgeous, and the redwood forests are right there as well.
Just google "lost coast california hiking". It is truly one of the most spectacular pieces of caostline on the west coast...and it is super remote.
I would also check out big sur, though its a pretty far drive for you.
the redwood forests are gonna be constantly 52 degrees, gray, and damp. its not real fun backpacking when you can never dry anything. but it will be a sick trip regardless.