So, I've had a '79, '85, and I currently have a '96. I love these trucks.
The 351 is a much better engine to have than the 5.0. You'll get the same mileage with either (just looking at engines here), but the 351 has noticably more go to it.
I don't believe that the AOD was put behind the 5.0... maybe they changed things for the later trucks, but my '96 is a 5.0 and has the E4OD (C6 derivative), my '85 was a 351 and had the same.
It's not IFS, it's TTB. It's not quite the same. If you have weird wear on the tires, it'll need an alignment - make sure that the alignment shop knows TTBs; there's something wonky about how to align them properly, and I'd go so far as to say that most shops don't know how to do it right. Once it's dialed in, though, it usually doesn't go out.
The autolocking hubs suck. I've never seen a set that actually worked. Luckily, swapping to manual locking hubs runs about $120 if you buy all-new high-end parts, and it takes about 20 minutes a side if you like to stare at things and drink a beer while you work.
I also recommend staying away from the push-button transfercases. Ford started with a floor-shift type, and toyed with push-button, then went back to a floor-shifter.
If the top has been taken off, it likely will leak. Luckily, Broncos were designed so that even if they do leak, it doesn't affect the driver or front passenger. If you look at where the top bolts down and can see the bolts, it's likely been removed. (Ford puts covers over them, people who like to pull the top usually are too lazy to put the covers back on).
There's just enough room in the back to make you think you can sleep back there comfortably with the seat folded forward. If you're over about 5'6", that's unfortunately not true. With the seat removed, however, it's fantastic. So, if you're going car-camping, pull that back seat out.
Check that the rear window rolls up and down properly. They're a power unit, and they're a right bitch to get at the motor when it goes out.
If your state allows for it, get rid of the Y-pipe cat unit. Things are horribly restrictive. You'll probably want to keep the single-exhaust just for packaging reasons (there's no good way to fit a decent dual exhaust system under there with the front driveline in place), and I recommend keeping at least some sort of cat in there, but that y-pipe cat thing is particularly bad.
If the timing set hasn't been done, do it. That's what killed my '85. I guess Ford decided to use a fiberplastic timing gear... you can guess what happens to one of those when it's had a timing chain pulled over it for 100k miles.
Hope that helps!