I've got 170,000 on my 2003 Z71 4 x 4 extended cab. I bought the truck with 75,000 on it and did a fluid change right away, then every 50,000 after that. It still runs like the day I bought it. I'm selling that truck now because I just bought a 2013 to replace it. Let's hope this one is even better than the last one!
Carbon,
I use car-parts.com when I'm looking for used parts. It will list junkyards that have the parts that you're looking for. Once you enter what you're looking for, it will show you the list of places that have your part in stock, and you can sort that list by distance, cost, etc. Good luck to ya!
Jake