Had a 15 year loan (dealer finance through Bank of America Specialty Vehicles), 4.99 simple interest. Paid it off in 7 years, didn't have to make arrangements, seek permission or anything. The additional payment each month was applied to principal,the scheduled payment had the interest taken out of it. Final payment I made was the payoff balance I obtained from B of A, and just like a car loan that figure was good for 10 days. Everything ended happily ever after.
Edit: OP, you're more likely to get an long term note via dealer financing than a retail bank or credit union. That was our experience; our credit union doesn't finance longer than 96 months on any RV, and only financed 75 % of the purchase price. Our experience was in 2012, things have changed, and it's entirely possible longer term financing is more depending on credit score.
