first, it would help if you told us what type of RV(class A, B, C motorhome?) and model, instead of a 6-7 seater RV.
second, not sure how much research you've done on Redwood NP, but it's pretty big and there's lots of options to drive and visit.
do you plan on camping there or just make stops along the way?
and 299 is windy and you'll need to pull over if you are driving only 45mph, to let traffic by.
there's no high elevation along there or 101. DON'T take Highway 1 south of Leggett. not for first-timers. stay on 101.