We're a family of four too - in a 430. Our kids are very small at the moment (age 2 and 4) and we all squeeze in for the occasional night, but we wont do when they are older. We take an awning and small tent for longer stays and use the small tent for extra sleeping space. The grand plan is that the kids stay outside the 'van! However, it is useful to be able to all squeeze in for the odd night, especially on long journey stop-overs or the last night of the hols when an early get-away is needed the next day.