We have built some mini campers so we could travel cheap across America. Everything went rather well for us. I’ve built two campers the first one was the smallest. Camper 1 was only 8′ x 4′ but camper 2 was 9.5′ x 6′! There is lots of information about these campers on my website #RickMercier.com.
Check them out you might want to consider building one.