Welcome to the TDR Ron! I bought my '95 2500 out of the local "truck trader"--or some such bi-weekly mag with pictures of trucks for sale. I got it out of Palmdale from a nice old guy who bought a Diesel pusher RV and didn't need the Dodge anymore. I ended up with a good, used, bombed, 2500 with 57,000 miles on the odom and about $5,000 worth of upgrades. Paid a good price for it. I've owned it 4 years and put 90,000 miles on it with NO problems!
I have always had good luck buying used cars. I inspect everything I can, and then sit in the vehicle etc. So far I have always gotten good cars & trucks.
There are a number of things to inspect on these trucks. Keep reading the forums to find out what.
Also it is good to run a Car Fax on any truck you find. But mostly I go by whether or not the owner is an honest person and the truck looks good and un-abused.