The first time our church did Group VBS it was using Egypt: Joseph's Journey. We really took the idea of these being "Egyptian Homes" seriously. We asked family leaders to decorate their rooms, and I even devoted three pages of my Egypt Volunteers Guide to what you could find in an Egyptian Family home, and told them to make sure to consider whether they wanted to decorate for a wealthy or poor home. Was all that necessary? Not really.
Granted, the "family home" pages I did helped with marketplace decorating too, so I don't regret doing that. But for family/tribe/group leaders, that sort of prep/decoration is really not essential. Family rooms can be absolutely undercoated and it's no big thing.
If you have some woven rugs or blankets to throw down on the floor of family rooms, that's a nice touch. Using a low stool in stead of a chair is both historically accurate and keeps volunteers closer to kids level (sitting on the floor with them does that too--but some volunteers may feel more comfortable with something to sit on). Bringing some throw pillows from home can add some practical cushioning (and is also historical).
This is not a great picture above, but I think this was one of the coolest (and smartest) set ups. The rugs naturally showed the kids where to sit. The focal point in the center gave kids stuff to look at without drawing their attention behind them, away from the stool where the group leader sat. And I have to mention that stool...cause that stool is so much like what Egyptians used it's uncanny.
And here's our sign stands. I think we left these in the rooms on the first day (so kids could find their rooms) and then moved them to the marketplace to use there. We reused these to hold columns several years later when we did Rome.