That price is very reasonable, I've seen a lot worse for a lot more. I know the guys in Montana, North Dakota, etc are spoiled and can get them cheaper, but in Pennsylvania or Florida to find one that nice you gotta step up and grab it when you can. You can buy a rust bucket for less or start with a super nice one and save yourself a lot of work and money in the long run.
Looks like a really nice solid cab. Just how many did that guy have ? Looks like a lot of them in the background.
Let me give you a tip. Take some Ospho and a red scotchbrite pad and scrub that body, bare spots paint and all. Immediately wipe it all off before it dries with a clean cloth and you will be amazed how nice the body comes out and how it will help keep rust from forming. Do a small section at a time, and even the paint will shine up pretty nice.
Don