Steve,
I don't believe there is a direct parallel here in the States.
There are people who purchase campers and recreational vehicles (R.V.'s) and then travel around the country (lots of them tend to be older folks, retirees), but generally speaking they travel alone, not in groups. There are even towns which deliberately cater to this clientele. For example, the climate in Yuma, Arizona remains quite mild all year so lots of older folks ("Snowbirds," as the jargon goes) in R.V.'s stay there every winter, then move on when spring arrives. Kind of like an annual migration. These are not destitute people, mind you. They spend their dollars.
Although it may happen in isolated instances or under unusual circumstances (i.e., natural disasters such as hurricanes), banding together in groups and pooling resources is not an idea which occurs naturally to the American mind, at any economic level.
-Paula