Suggestions...
They are great vehicles. Of course test drive it to make sure the tranny shifts OK. Problem is those are the better versions of the 700R4, but if people drive them around in overdrive it still screws them up from the constant shifting.
Check the steering box area (shouldn't be a problem for a stock road driven truck), check underneath for signs of leaks, just the general stuff.
I don't know if you will be able to really get a good look at the reciever hitch, but try and check for rust. If it is really rusty you may think about dropping the gas tank and taking a look making sure it won't rust through any time soon.
From what I have heard, replace the fuel pump at around 150,000 miles. They usually go out around this time, and it is much more convenient to replace it when its your choice rather than when it goes out when you're hunting. You have to drop the fuel tank to do this anyway, so make sure you run it out of gas first.
Go ahead and get the 1/2 ton. Then get a 14 bolt, slap it under the rear and 8 lug hubs on the front and go. Thats what we did. You don't have to worry about ABS either. The ABS sensor on those models had the sensor in the output of the T-case sensing driveline lockup, not the individual tire.
