Our favorite camp ground is Gualala Redwood River Park. It it off of Hwy 1, about 45 minutes past Jenner. It might be a little more than the 2 hour drive, but in my opinion, it is worth it. The do have RV compatible sites, however, they do not have full hook up which keeps the campground very pretty and tent camping friendly. These sites are generally located in one area of the campground. It is situated on a mild river which flows on down to the ocean. I grew up camping here, and have recently re-discovered it with my own kids. We just love it. It is very quiet and peaceful. Here's the website. There is not really a lot of hiking to be done there, but you can walk down the road about a mile to the town of Gualala. There are also some pretty nice beaches nearby. (You would need to drive to these, however, as they are all along the Highway).
http://www.gualalapark.com/