[CountD]

Depending on the state they may have a TRANSIT plate. Which would be good for you.

Also:

1) Insurance - get it insured in your name
2) Don't carry the cash. I can't blame people for not taking cashier's checks anymore. What is also an option that I have done is that once you are there and you CONFIRM the car is legit, has the legit VIN and legit paperwork you can have it wired from your bank to his/her account.
3) Check the tires. How old are they? Get new ones if old or suspect.
4) Check the oil. Maybe get it changed.
5) Always carry a fire extinguisher and basic kit of basic tools and belts
6) With your transit plate/insurance/etc you are good to go and enjoy the ride.
7) It's one of the best ways to buy a car - an adventure for sure.