I'll take a crack at this. Depending on where you live, look for rust and rust. On the inside of the drivers side frame rail is the fuel tank. It is notorious for rusting out the rail. A lot of the Wags I've looked at have had the air tubes welded/cut/bent shut. Once again, depending on the emissions testing in your area it's hard to get all the right parts back on again once they're off. There is a lot more useful information than I could ever give you on
www.off-road.com/~ifsja including how to buy a Wag. Happy hunting.