Maybe someday when I'm reaaallly old!
Unfortunately that will come quicker than you think. My suggestion would to be plan backwards, that is, where are you going to be when you are 92, how will you survive. What are the steps to get there.
I am going to die when I am 86; how do I know? In my 30's I was doing some retirement planning and looking at insurance annuities (didn't go there). In the planning/application process they did a health/heredity/life expectancy study and determined I would probably check out around 86.
Hopefully your children will be the type to help out when you get really old, kind of a payback for the years of child care... do have that discussion with them, it's an important part of your plan.
I have been full time RV'ing for 11 years now. I spend about $75k a year on travel, maintenance, food, RV parks. MY RV and truck are paid for. I tend to live on the high end of the full time lifestyle.
I have also volunteered at different state parks, national parks, private campground, National Forest Campground every year, sometimes only a month, sometimes longer depending on how much fun I am having.
In my travels I have met many women pretty much in the same situation that you have. Single Senior with an adventurous nature. Most tend to not move very many times in the year, spending several months in one location. Several have semi-permanent jobs at private campgrounds working in the office in exchange for site rent. Watch the movie Nomadland...
Here's the part where it may look like I am gender bashing but it's not my intention, just an observation of my environment. Most women have a hard time full time RV'ing, either they are timid about moving RV's around or don't have the mechanical skills to do the maintenance. There are extremes to both ends of that equation, my current neighbor lady in her 80's does 95% of everything as her older husband is starting to have age related difficulties, but they keep going. 2 doors down from them is a young family, early thirties, 1 child, the young lady is the primary bread winner, he is a stay at home dad, she does most of the maintenance and is an excellent mechanic. We all figure our own way of doing things.
Purchasing and RV. Never buy one more than 10 years old. Not enough space here to fully explain that, internet research will debunk or support that statement. Keep it small, something you can easily handle. If you decide you need bigger later it's easier to trade up. Pay cash for the RV. I shopped RV's by deciding how much cash I had, then finding out the max square footage that amount would buy. Just one way..
If no one has mentioned it, take a look at Medicare Advantage Plans with a zero monthly premium.
It's good that you are forward thinking getting really old. There are no absolutely correct answers here, only decisions to be made that take your life in a new (or old) direction.