I love the wagons. Problem with them is, the drivetrain is so old and underpowered by todays standards. Parts are slightly harder to get also. They are sweet for small towns with backroads, but around this area it's a pain to drive something like that imo. My CJ is pretty slow and just able to keep up with traffic.
Best thing to do if you wanted one of those would be to buy one that already had an engine/drivetrain swap done. That thing has a flathead motor in it and may not be 12 volt either. If you want an older Jeep that is easier to get parts for and has some modern stuff on it like, disc brakes,power brakes/power steering than look at 76-86 CJ5,7,8. You should be able to find one in decent shape for around that $3500.