We get this a lot. We're sailing cruisers - similar to the van thing, except on water and you use wind and pull on bits of string for propulsion, with the diesel engine only a secondary (but important) means.
Especially from the mate's mother: "When are you going to stop this nonsense and get a real job and a home?".
There's a whole community of us global travelers who have shunned the whole "being an adult" thing.
I know several people that have been backpacking and doing the working-holiday thing for 4 or 5 years. Never staying in one city for more than around 3 months, and moving countries when their working holiday visa expires.
Their families have mostly been saying the same thing. Settling down isn't for everyone.
Funny about the adult thing. When I managed other peoples computers, had I fucked up really badly, about 1200 people would've not been able to do their work and some company would've potentially lost a few million buckazoids. If I were to fuck up really bad when sailing (or boat maintenance), I and those nearest and dearest to me would die.
Especially from the mate's mother: "When are you going to stop this nonsense and get a real job and a home?".