400 sq/ft footprint....

[considerations]

I had a lot of fun exploring those tiny houses on wheels, but I moved on for the many reasons.  One of the real detractors in my mind is that most of them have no "bathroom" facility.  No toilet facility to be precise, and sometimes no shower.

That tends to put one in a dependent situation.  Either you have your own place where sanitary and personal hygiene facilities must be accounted for separately, or you may have to "rent a space" where communal facilities are available, or you are parked on someone else's place, and have to use their shower and toilet.

I don't really like any of those options.  So, for me, the only answer is to build big enough to accommodate those necessities.

When considering permanent living, the cabin sized ideas on this forum seemed the more reasonable option to me.