My first vehicles are just carts and bicycles, then as soon as I’m able, I retrofit a tank, making that my mobile base.
I clear it out, put heavy boards on the front side, and heavy stow boards on the other sides, put security cameras in the corners, surround it with headlights, add rams on the front, 200 liter drums on the rear, and ultimately convert it to electric/solar.
That gives me a 7x11 base with a 5x5 storage/crafting area, 3 beds and 3 seats up front and a 2x2 curtained area to the right of my seats/beds. I put the only window in front of that 2x2 area with a mirror inside of it which allows me to open one curtain for a periscope view out of the window for when I can’t use my security cameras to drive. It’s very slow, but awesome.