I'm looking at a chevy at a dealership at some point today. It has 154k miles on it with the 6.0. They are wanting 13k.

I have some questions

what should I look for while walking around it and test driving it.
rust spots under the wheel wells and hitch area. Any other spots?
Ill be using this for towing stuff and I believe it can tow up to 8600lbs with a empty bed.
Any other trucks i should look at vs this truck? The used car market in WA is pretty rough so I know not the best price.