Hey their LawChick,
Welcome to the Forum!
As the guys already mentioned, the wheel chrome flaking off is pretty common. You can choose to just live with it, buy new wheels, or opt to have the wheels sandblasted, and powder coated either in what is known as Hyper Black, or Black Chrome, or a variety of other colors for around $50 - $60 per wheel plus the cost of dismounting, and re-mounting the tires which is a fraction of the cost of new wheels. Another option anyways.
As for your rust, the exhaust should be a pretty common issue with the road salt issue, and so on. If the rust, or corrosion on the frame part of your PT is just surface corrosion then it is not a big deal, however, if their is any type of more serious corrosion, then I would throw up a little caution flag, as the frame/unibody construction of your PT is part of its structural support which helps in the rigidity of the body itself. If it is compromised in any way, it could become a safety issue!
To put it in simpler terms, lets say the wheel studs that hold your wheel on your car were seriously rusted through. Even if you spray paint them to look like new, the damage is done. You can drive the car with them like that, but you could run a very high risk every time you drive over a pot hole of breaking the rusted out studs and having the wheel fall completely off the car causing a serious accident, and could hurt you, or others! Any Structural Component that has corrosion on it is just as serious, if not more so, and just to be safe, it is something that I would recommend getting checked out before you buy the PT just to be safe.
I would start by calling back your Mechanic and ask him if he thought the corrosion on the undercarriage could cause structural issues. If he confirms its just surface rust and their should be no issues in his opinion, you should be covered. If he says otherwise, or is not sure, I would big time recommend getting it looked at!
If at all possible,
especially before having the Dealer repair it, I would recommend either having an outside reputable Body Shop take a quick look at it, or if you could possibly get a couple of pic's of where the rust is at and either post them here, or email them to me, I can tell you if this would be a safety issue or not before the Dealership tries to clean up, or cover over the damaged area which is pretty typical for Dealerships to do.
I don't mean to scare you, but rather as someone familiar with paint and body, I just want you to be safe, and enjoy your Cruiser for many, many miles, and many smiles! Always better safe than sorry!
Go easy, and please let me know if you have any questions, concerns, or if you would like for me to look at a pic and try to evaluate the damage for you anytime.
Take Care,
Candyman