The interior panels come off pretty easily, once you know where the clips are. I can send you a pdf of the FSM detailing the steps. You'll need screwdrivers, a T20 Torx screwdriver, sockets for the seatbelts, and interior trim "clip removal tool". Be prepared to replace a couple of the old clips if they break during removal. The entire interior basically snaps together. There are some pics in some of the stereo install threads (to get to subwoofer). I took mine out to install overhead DVD, XM antenna, and backup camera in the tailgate.
More details on your leak might help as well, and potentially stave off doing some unnecessary work. Pics, details on symptoms of the leak?