The rough-and-ready, improvisational quality to life on board is reminiscent of a long trip in a sailboat: privacy and fresh produce are in short supply, hygiene is basic, and a fair amount of the crew's time is spent just on a maintaining and repairing the craft.
There're more similarities in the preparation involved in getting into space and:
The first explorers who crossed the ocean in sailing ships didn't blithely set off without considering the practicalities and logistics. Before they even left land, they tried to figure out which kind of timber would hold up the best and what kinds of food would keep on a long voyage.
Must say I had a similar idea - I thought that the Inspiration flyby of Mars trip with two people on-board sounded just the thing for a long-distance double handed sailing team.
BTW: I like double handed sailing.