I agree with taking baby steps.
Renting a van I a good idea, but can be expensive if more than a week or two.
We all tend to over estimate what we really need, and you don't know what you really need.
Sometimes there is a big difference between what we think we want and what we actually need, although different strokes for different folks as they say, also applies.

Can I suggest buying a small cheapie, say an older Hi Ace Camper Van and go for lots of shorter trips and base yourself at home (before you sell it), so that you are not under pressure to sell your house.
You can then take your time locating where you want to buy a smaller dwelling. In other words perhaps test out where you want to live whilst in your camper van.

If you buy a cheap van, and select it carefully, you won't loose much if anything when the time comes to sell it, and it may be much much cheaper than renting, especially if you use it a lot. You may decide that a small van may suit you after all, and may decide to just change up to a newer model, with the features that suit you.

I find small is good for me provided the weather is hot enough to live outside, under the awning, (much better to eat and cook outside too), and you are out in the fresh air, and meet more people.
The only draw back with small, is cabin fever when forced inside due to cold weather, but you can work around this, go shopping or to the pub etc if it is wet, and don't travel to cold locations.
Good Luck, and make your own decisions.