The 4th may be booked for any rv spaces already. Even the Dam launch site can fill up for launching. There are not a lot of RV parks at or on the lake unfortunately. The lake is beautiful and huge and will be warm and comfortable at that time of year. The fishing can be awesome. Bald Eagles, deer, and lots of other critters can be seen.
The name of the marina slips my mind but the one major one has a beautiful ramp. As far as slips you need to start making calls now.
There are a couple of nice RV parks in Oroville so if you can get a slip for the boat your drive will be very short. About 20 minutes or so.
There are two Indian Casinos and one has a nice RV park. It is fairly new. We stayed there for a weekend trip to get away. We lived just a few miles South of Oroville then. When going to Oroville lake it was a simple day trip for me. Less than an hour from home to launch,.