Not much in the way of hidden rust issue here in CA with the trucks, except below the battery from leaking battery acid. Sometimes you find it along the windshield, otherwise it tends to be just surface rust. If the tires are bigger than 28 inches, expect it to be a little gutless. The pre '86 plastic interiors don't seem to hold up well, at least not with the ones I have restored.
Not a lot of hidden issues with the motors either, other than the plastic timing chain guides and lazy owners who don't respond early enough to the rattling noise, and have the chain eat through the timing cover. Most original engines will have some type of oil leak, usually from the head due to not installing the valve cover gasket correctly, same with the oil pan. Other leaks tend to be the front seal on the timing cover as well, or water pump. The valves and injectors on Toyota engines are normally noise, so don't be alarmed with some of the noises when sitting still. If you want to get an idea of what the trans/engine sound like w/out road noise, you can put the transfer case in neutral, then shift through the gears w/the engine running, as if you are driving it on the highway. This isn't wont tell you everything since the engine and trans aren't under a load, but it is helpful.
Price range is going to vary greatly, stock beat-up should be anywhere from $1500-2500, clean stock can be as high as $5000. If you aren't sure you are going for extreme side of the wheeling game, IFS('86-88 2nd gens, and '89-95 3rd gens), are very capable off road, and due to not having the factory straight axle tend to sell for less. I am not trying to sway you one way or the other, just letting you know about your options if you are new to Toyota's as well as wheeling.
