Sorry, read the OP wrong. In your shoes, knowing what I know, I'd probably ask for the cashier's check. Yes, they can be faked, but I've seen a lot of good counterfeit cash of late, using the same scanners, software, and printers you can use to fake the check. And there's a method for people to treat the money so that it reacts to the pens in a similar fashion to real cash (no, I won't tell you how).
Probably the best option is to agree to a check, meet at your bank, and turn over the keys and title after the bank has run the check (so long as the computers are running, the bank should be able to verify it is a good check pretty quickly).