I have actually replaced pocket doors that were worn out. It mostly involves removing the retaining trim around the door opening so you can remove the panel, and most of the actual operating hardware is on the door itself. The track is really the only thing in the wall, besides a couple of nylon bushings around the bottom of the door slot to protect it.
The most important thing to keep in mind around pocket doors is not to penetrate the door cavity with any nails or screws, or you will destroy the door when you open it for the first time. Also, remember to check for plumbing and electrical lines in the planned door cavity before you go to the trouble of cutting away the drywall. You may find it structurally appropriate (and it is most of the time) to remove the wall all the way to the ceiling and install a structual header above the entire door and pocket, then re-drywalling both sides.
You can buy the door kits in two ways. One is just the hardware only in a box about 3-6 feet long, by about 8" square. The other is as a pre-built pocket frame constructed of 1x2s with the hardware included. You will need to buy an appropriately sized door blank to fit the kit. I would go with the pre-built frame every time. It's not worth the hassle.