If you are NEVER going to use the RV... sadly it is probably best to sell it now. The value will only go down and the maintenance, insurance and storage fees will only add up.
I would consider arranging low interest credit cards, home equity line of credit, some cash (not more than 30% of savings) or a combination of all to be able to pay off the RV loan at the time of sale.
Once some of the debt is paid (RV cash value) and you start to apply storage fees and insurance to the debt (in addition to the previous regular payment) it should get paid off faster with less monthly pain.
Probably too many details and personal info to discuss here. But put this plan in front of a banker or personal finance person and see how the numbers drop out.
There have been plenty of posts over the years of similar situations.
You are far from alone on this. Best of luck.