Yours is such a basic question I'm going to suggest a consignment lot and nothing else.
They'll do the advertising, store it, show it, help with the payoff timing, let you know IN ADVANCE if you're going to have to write a huge personal check to rid yourself of the rv(there's a VERY good chance you'll have to), and they'll deal with the buyer, your bank, their bank and the licensing questions.
They'll at least guide you all through the process because they won't get paid if they don't personally guide you.
Have you called for a payoff amount?
What vehicle(exactly) and with what options and miles?
We can tell you today, pretty close, if the net will be $5,000 to you or if you'll pay $30,000 from you.
If your payment is $1,000 a month and you take five months to find a buyer, you should have sold it five months earlier for $6,000 less.
Keep that in mind. Unless you need a hobby, sell it to the first person who can buy it for anything that doesn't financially destroy you.