I would check the little known area's, under seats look nder the bed (underneath the truck) and on top of the spare tire to see if it is full of mud or if it is rather clean that tells a lot about use. Also look under the plastic holder behind the seat, depending on what you find will tell you about the previous owner. I personally found lotsa leaves and grass--I am guessing they left the windows down alot especially since they were smokers (burnt seat). Always check fluids and see what color they are and if they have any weird residue in them. Make sure the 4x4 works lot of people dont check it especially if buying in the summer. Maybe even take a peak at the fuse block and see if anything has been rigged up in there oddly.
Just one other thing, when I put my aftermarket stereo in I had to cut the wires to the old one but I could put it all back together real easy and cheap i.e. crappy might want to take a quick look at those too.

 

I can't explain it,
1095 days x 2 trips per day x (at least) 2 complete window cycles =
Over 8,000 window cycles (driver's side)
Passengerside maybe 20% of that.

(I've even peeled back the trim looking for the start of the crack.)

I have known about the crack since before I bought my truck and am always gentle with the door even though the consensus here is that the window causes it, not rough door operation.

 

About checking the 4x4. When I drove the trucks, I flipped it in and out several times. No crunching or grinding. But at the same time, with it being spring, how do I verify that the front wheels are infact driving the vehicle and not just continuing to spin freely? I guess it felt a little different when in 4x4, and in one of them the rear differential stayed locked when in 4x4 hi.

Thanks a bunch for all the tips so far. I drove a couple at a dealership on Friday and when I came back the salesman was blown away at what I had to say about them. One was a total POS. Leaking door, brake light, strong smell of cigarettes, the differential I mentioned above, among other things. Probably got him stirring in his shoes since usually the test drive gets the customer excited and ready to buy. One of the trucks was pretty nice, but still had a couple minor things. (No bedliner/bed scratched badly, dirty interior)

 

I found tools behind my back seat. Whoever owned it before musta lost them down there. They had some rust on them too. Probably just from water that leaked through the sliding rear window.

 

Tools ain't so bad, better than assemblyline worker.
Now, that can really stink a truck up.

Stang6835, if you really want to impress the salesman, lower the spare and check how bad the sidewall is cut up. If the previous owner didn't take preventitive action. the spare is worn down in an 'X' pattern from underside rubbing.

 

Raoul, just imagine how the Batcave smells. If it's so 'secret', then either they killed all of the workers and hid them in there or Alfred had a Bobcat, one of the two!