If you want to stay closer to home, there is the lower Kern River. It
is a two day trip about three hours from LA. First day is mostly class
three, very scenic. The second day is class 3-4. Great for
enthusiasts, and beginner. I travel five hours down there all the time
just for that run. The company I would recommend is Kern River Tours
(www.kernrivertours.com). I have worked alongside most of the
outfitters in the area and KRT really seems to have their "act"
together. If you are looking to learn to kayak, I would recommend
Sierra South (www.sierrasouth.com) in the same area. They have a lot
of boats, awesome instructors and a lot of experience.