Its entirely possible there could be some stuff somewhere that could freeze. Really depends how cold and how long its exposed without heat.
Assuming the basement factory heat ducts are installed properly and all the water lines are contained in properly heated areas, you should be ok.
The way the factory installs stuff with such carelessness one never knows for sure and Fleetwood were never known to be good from my long experience with them.
One area to be concerned is if you have a ice maker make sure that water supply line is blown out and no water gets through as basement heat or not the solenoid will freeze and break.
Remember if its say 15 above and sitting still with heat on is one thing and driving down the road at 60MPH is a entirely different deal.