For them to drive it (even with you in the vehicle) make a copy (or picture) of their driver's license and their proof of insurance, because if something happened while your prospective buyer was driving it, you want HIS insurance to be primary, not yours.
As for funds, agreed that wiring the funds is the only way to go (unless the buyer has a sack full of greenbacks). Do the transaction at the bank or credit union if there's a payoff involved, OR do it at the DMV (just in case any questions or issues arise pertaining to the title transfer).