If ya find a truck ya like make sure to get the VIN # and post it in the OASIS forum and get a report for the truck. This will tell you the most you can find out about the truck.
For in person inspections. Other than general inspections for every vehicle, check the Degas bottle cap for any white chalky residue that would indicate puking.
I bought mine almost 2 years ago with 49k on the odo and with a clean oasis. It now has 83k and only problems it has given me are a plugged EGR valve (45 minute DIY cleaning) and currently has an injector or two sticking making it start rough when cold, otherwise runs great.