You'll be very hard pushed to find a family room in a hotel or Logis de France to take what amounts to at least 2 doubles and a single full size bed (the kids aren't exactly baby cot size, are they) as rooms with 5 full size beds are not common here. Are they in the USA? You may find a B&B through Gites de France that has one, but rooms that big are the exception, not the rule. Best look for two rooms for 5 people. Re availability, you aren't likely to stumble across a room this size without checking in advance. I recommend to anyone travelling June to August to book in advance - we are heavily booked up to mid-September already.