Seller refused sale because I wanted to use a cashiers check

I understand the seller's hesitation to use a cashiers check. They are commonly forged and you're out of luck as a seller when you get a bad one. The money is taken out of your account and you no longer have the RV.

I understand this deal is long gone, but I too prefer cash (withdrawn together at the bank) and title transfer at the DMV.

You might consider paying the fees for an escrow service if a similar situation comes up in the future.