Well, you'd better get it cheap. It's an old truck with a few inherent problems.
1. Those trucks before 1997 (I have a '97) have a single thermostat water crossover pipe. They are known to overheat under load. It is upgradeable to the dual thermostat setup found in '97 and later, and it may be best to do that if it hasn't already been done.
2. '94 and later trucks have a computerized Injector pump. These computers are known to go bad, as they overheat. You can buy a relocater kit to move the PMD it is called to a heat sink at a cooler location than on the side of the pump. Mine had that done with a hillbilly setup, I need to buy a nice one, as mine starts hard when hot, and I belive that is the Issue. (At least that's what the 6.5 performance shops say)
In the end, If you do some research, and are well informed and mechanically inclined, they can be a good truck. Mine has 140,000 on it, and I bought it with 126,000 last september. It has made 2 500 loaded mile trips for me, and other than having less power than a person would hope for, it is serving me well. It will get the job done, just not as fast as a duramax or powerstroke or cummins. If you have a lot of hill country you plan on hauling your tractors through, you may be annoyed by that particular truck. An A and a 50 is what, 9,000 plus trailer? That's more than I'd want to pull through hill country with mine. I pulled my 450 Diesel farmall with loaded tires on one trip, weighd about 7,000 I guess and that was plenty for me.
Hope this helps! -Andy