Overheated 22R-E - What could be wrong???

I just bought my first Toyota pickup last weekend. It's an '85 XCab SR5 with the 22R-E engine . The truck looks to be in excellent condition except that it doesn't run. The previous owner told me that it had overheated last summer and seized up. He had taken off the valve cover and power steering pump and pulled the spark plugs and that is the condition that I received it in. He sold me the truck for $500 because he said that it is going to need an overhaul or a new engine. Although he said that it is seized up, when I got it home I tried the starter and it does turn the crankshaft over without any grinding or scraping noises. Since it does turn over with the starter motor I don't think that it is going to need a new crankshaft, rod bearings or main bearings to get it running. I checked the oil and although it registers a little higher than the full mark, it doesn't appear to be contaminated with water. I didn't see any milky/cloudy residue on the dipstick. My first question to the group, is "What damage should I look for after it's having been overheated enough to make it quit running?" This is just my first question. I suppose that there will be many more in the coming months. (Years maybe???) TIA. Jerry