If your retirement income is really going to be $6000/month, IMO you'd have to work HARD to make your expenses exceed your income. I'm jealous.
My
primary reason for living in my RV was to save on monthly costs and still have my own home, so I bought a couple of campground memberships up front so that my monthly space rent and utility costs would be $0.
I'm not the boondocking sort - I like my electricity.
After a year of snowbirding up and down the west coast, I decided where I wanted to stay, and now go back and forth between two recreational RV parks that are 3 miles away from each other. My monthly space rent and utility costs (except for propane, which I don't need much of except in Dec and Jan) are less than $100, which is the amount of the annual maintenance fees for both parks, set aside monthly.
Because they are recreational rather than residential parks, electricity is free. I use a space heater and bought an induction cooktop, so I never use my propane stove or oven.
I set aside $100/month for RV maintenance and repairs (when they hit, they can be big).
I have one cat and don't feed him cheap food, and I set aside money every month towards possible vet bills.
When I was traveling, except for my semi-annual relocation weeks, I was only moving every 2-3 weeks and had no toad, and I budgeted $90/month for gasoline, which evened out over the course of a year.
After the loan payment on the RV, my biggest single expense is actually for Verizon data - since I'm not stationary, my internet usage all comes through my Jetpack. But I don't use satellite TV (I stream/download everything with a computer hooked up to my flatscreen), which it seems most RVers do have, so I suppose that cost goes into my data plan. It's just something to think about that isn't a large expense for a sticks-and-bricks, but can be for people who aren't stationary.