Pretty odd to see the lower doors rusting. I know a lot of other Toy/Lex models have that issue and I’ve personally dealt with it a number of times but I don’t think I’ve seen that on a 100, or people just don’t post about it. Undercarriage definitely has some scale that was most likely rattle canned over but it doesn’t look terrible if you ask me. I’d be more concerned about the body rust, that can be tricky to fix and not have it come back after a few years. Lucky for you, once you fix the body rust, with TX being as dry as it is and no winters, it should serve you many years to come.