I have a popup that would probably suit your needs. No it's not for sale.
1986 Coleman Columbia popup. It has two full size beds and the table folds down into a third bed. You could put both children in one bed and the parents in the other. Or one parent in each bed with one kid each.
Trailer has an 8 foot box and weight 950lbs dry. It has one battery, one propane tank, a 2 burner stove, and a 5 gallon water jug for the sink. In all truth though I never use the stove or the sink, I use the trailer as a rolling tent.
It has NO heater and NO bathroom.
