My last car being a '97 Honda Civic that got 30/33mpg (I bought it new), I wanted something that got similar fuel economy, so a full-sized van was out of the question.
That left minivans, but I wanted something with a metal high top, so that narrowed my choices down quite a bit further. I also wanted something newer with less than 80,000 miles.
I ended up finding a 2010, then 4 year old, Ford Transit Connect with less than 60,000 miles that's in great shape and gets 27mpg on the highway.
I love it, it's a great car. I consider it a car and not a van because it's so small and is built on a car chassis.
It should be mentioned, that I am not living in it, full time or part time. I only use it for camping, and it's perfect for that.
Originally I thought I'd use it to live in full time, but now that I've slept in it multiple times, I've come to realize that it's just too darn small for that.
I know people live in cars, but I have too many toys, namely bicycles, kayak gear, archery stuff and a banjo, that I don't want to part with, so it just won't do.
Eventually I'm just going to have to accept the fact that excellent fuel economy and roominess aren't going to be a combination I'm likely to find.