Like previously posted, most bank branches aren’t going to have $45,000 in cash. And if they did, they aren’t going to cash a cashiers check for that high an amount for a non customer, even if it’s their own cashiers check. About the only way to have this style transaction go smooth and safe would be to tell the buyer to meet at his bank where he can have it arranged the cash is available and he withdraws that amount from his account and gives it to you on the spot. Hopefully you have an extremely desirable rig priced too good to be true because your need to not involve a bank is going to run off 99 out of a hundred potential buyers.