no kids, but personally I would suggest the TH, separate garage so they have there own room, put two small desks against the front wall so they can still lower the beds and not get in the way, room to haul there bikes or whatever when your camped. I would also suggest either a pull down screen for fresh air, OR even better the add a room deck kits for the ramp door to open up there play area.
as said most now have ducted air and heat in the garage area ( or there own unit )so they should be very comfortable, look for an Arctic package / whatever its called based on the manufacturer. hey can never have enough insulation. also most have a separate door from the garage so the kids can come and go on there own I think the toughest choice will be the lower bunk, should it be a Dinette? 2 couches? anyway good luck, and go look at them only you can really know what will be best for you.