Also, do a google search for RV blogs budget full time, or something like that. There are many blogs out there written by full timers on a budget. Often they list their annual expenses. You or I might not agree with their priorities or lifestyles, but they cover a range of options, and pretty soon you will get an idea of what is possible. Most blogs are only active for a few years at most, but they remain out there for you to read. Maybe some posters could mention some appropriate ones. Some that I have read, without links: (Just google them)
Tioga and George
Travel with Andy Baird
RV-dreams
rvroadtrip.us
RV boondocking the good life
myoldrv.com
interstellarorchard
travels with kevin and ruth
And there are plenty more. I would advise figuring out how to get to the beginning of a blog and working forward from there. Unfortunately the blogging websites make that a difficult process. But you can do it.