Ask to see maintenance records. Oil change intervals, filters (oil, intake, cabin), etc. How old are the tires and how much tread is left?
How many after market parts and tunes are on the truck? These can void warranties.
Is it lifted? Do the original parts come with the vehicle? Was the work done by a shop? Receipts?
Check the quality of the wiring on the aftermarket lights, look especially for “Scotchlock” splices/taps. Scotchlocks fail over time.
It’s common for after market backup lights to be spliced into the tail lights with Scotchlock type taps. Once again check the connections for quality work.
Crawl underneath to look at the aftermarket wiring from battery to backup lights, same with front lights.
If upfitter switches and pass through wires have been used, check the wiring connections. You want to see good quality crimp or solder connections, not the Scotchlocks.
If you see Weatherpak or Deutsch connectors, as well as relays for the lights, that is a good sign.
Ask if the plastic oil pan or the gasket have been replaced. If they haven’t been replaced and there are no leaks, it’s likely good to go. FYI, I’ve got a 2018 with the plastic pan. And zero issues at 70k miles.
If there are wheel locks, is the key in the truck?
That’s not very many miles for a 2017. The truck looks great
Best of luck!