My legs.

But, if I was forced to choose, I’d go with an RV, and then live out of it. No in-between. Why?

I have two preferred modes of living. One is without a car in a walkable area. The other is with a car, and my house is attached to the car. Everybody already gets walkable cities, but having an RV would warrant the freedom to be able to bring all of my possessions anywhere I want, whenever I want. For practicality, I’d use a motorbike for travelling after parking the RV. This is the only way I could own a motor vehicle–it must serve a purpose beyond merely moving a few people and objects between point A and point B. Else, I don’t want one.

The only cars I’ve been at all interested in otherwise are old Honda Stepwgns, the Peel Trident, station wagons, and, indeed, motorcycles. Still see no point in these when a hypothetical RV would be much better for a solo road trip, and when I can go on a vacation via plane or another friend’s car. I’m not going out alone.

I don’t like single-use items. I prefer everything I have be as multi-purpose as possible.

EDIT: I should probably clarify I would live out of an RV. It’s not just a hypothetical alternative, it’s something I’m considering.