I haven't seen it yet, but my Dads got his eye on it and wants to take it home. I unfortunately don't know to much about the newer trucks so give it to me straight if you would. Its a 1999 GMC Sierra 1500 4x4 with a tow package and a 5.3 liter, power everything, 21,000 miles and running for $21,000. It was advertised at 17city/22hwy fuel mileage. the Vin is 1GCEK14TOXE207754 (hopefully the 1's arent I's.. etc). Whats the deal with the tow package..rear end.. auto hubs etc. He's going to be mostly highway on it, planning on getting a travel camper on the back and 4x4in to places to camp on occation. What should I be on alert for?