In reply to Adam Moroz:
we started with an Outwell montana 4 for our family of 4, then upgraded to a Montana 6 so we had more space - both in the bedrooms and living space during grot weather. They are pricey - think go outdoors might have bought the rights to the older design of montana 6 to sell under their own brand name. Thoroughly recommended - albeit only 2 bedrooms and not the 3 you are looking for. There is someone in the Outdoor Gear Exchange facebook page selling a 5yr old one ...