Comprehensive "what to look for" second gen list?

Hi everyone

Later today, I'm going to look at this truck: https://boulder.craigslist.org/cto/d/boulder-2007-toyota-tundra-overland/7661837900.html

It's being sold by a self proclaimed mechanic (I have no reason to doubt him, but talk is cheap after all). I'm a little worried by the engine flush, as I typically wouldn't do something like that on engine or tranny unless there was a legit problem. Also wondering since *all four seats have been replaced* whether this is maybe a vandalized truck that has been sold and is being flipped. Trying to figure out how much that bothers me.

Aside from that, I've crawled multiple threads on this forum for the past few weeks, and wanted to make sure I don't need to be paying attention to anything beyond what's listed here (recognizing that I'm no able to take it to a mechanic for an inspection):

• Cam tower leak
• Ask about air injection pump failure (he actually has a bypass included with the truck that he's not yet installed)
• When was the water pump last replaced, and did they do the serp belt at that time?
• Rust - classic frame locations as well as bed
• Are the leaf springs thrashed and needing to go? Seen too many used Tundras with leaf springs at the end of their life

Again I am trying to keep in mind things I'll be able to visually identify and ask about in conversation. Thanks everyone for your time.

$18,500 for a 200k Tundra with a brand new Leer 122 with some various other work done. Potentially exciting.