They open up for reservations on the first of the month seven months in advance. From years of experience, if you are not on the phone and in the que by 8:01am with Reserve America, your chances of getting a summer weekend are nill. Have several weekends in mind so if your ideal time is booked, you can pounce on your second choice right there. They book ridiculously fast. They are running $100 per night, and well worth it. They include propane for the BBQ and dump the trash every day.
Two families of four should be no problem. Their capacity is 15, but a few summers ago we had two campsites for a youth group trip and had 22 on one of them at one point. Plenty of room for four average tents up top.
Here is a link:
http://www.orovilleareachamber.com/lakeoroville/floating_campsites.html They just added a 12'x 20' dock to the side which adds a LOT of real estate to spread out gear...or the snorers in the group (sorry Trace!). If you can get them, they are a blast!.
(Message edited by zipe on November 10, 2007)