Hwy 4, Ebbetts Pass. They must be kidding.
Wikipedia, not known as an RV authority says "Today, Ebbetts Pass is one of the least traveled passes in the Sierra Nevada. An extensive section of highway over the pass is less than two lanes with no dividing line. It has very steep sections with hairpin corners.[11] The eastern slope is particularly difficult, as many of the hairpin corners are blind, and steepen suddenly at the apex, making it necessary to shift to first gear in most vehicles. It is rarely used by commercial traffic and is not recommended for vehicles towing long trailers.[12]"
I, who have driven this road several times (in my 20-ft class C), agree with them.
If you are not going up/down the western slope higher than Bear Valley, then maybe OK.
My favorite Hwy 4 road sign:

This page has more info and videos:
http://scenic4.org/