Would your sons be more comfortable with a less ‘All In’ approach and start?
Unless you’ve been tossed on the street by landlord smaller steps can be very useful for you and your caring relatives.
Don’t know your situation or experiences in life but...
Have you spent an entire day at a local park, forest. Made your breakfast, lunch and dinner on picnic table. Can start with tiny-er steps with coffee and breakfast from a drive though or thermos and packed breakfast from home and hangout till lunch/dinner. Bet between your sons and you, you have a camp stove, 1-2 qt pan, good camping, sleeping pads and other items to practice.
I think a full sized van is better than a mini van because of its strength, frame, brakes and the price much the same. Either of those sons have van shopping ability? Get them involved.
I have a good friend, she keeps her home but uses her van for relaxing day trips to parks, events or things to see a day+trip away. She has a porta pot setup (bucket), stove, cooler, and simple sleeping arrangement. If she wants she can still pick a motel but can find a Walmart or boondock spot for the night. She has taken longer trips like xcountry from CA to PA but mostly stays within a couple states of home. She appreciates her home conveniences but yearns to see nature, new things, water, mountains, but not live in it 24/7
Have they watched Bob’s videos? If he is a guru of anything it is to find away to live your best life. I haven’t heard of him giving a date for the end of the world.