furnace / heat pump questions

[CHICKDOE]

ok, we were at crater lake yesterday and it snowed (a bit). but it was cold enough we tried to turn on the furnace. our 5th wheel has two dometec a/c's. the front one has a thermostat with 3 modes: fan, cool, furnace. the rear one has a thermostat with 4 modes: fan, cool, furnace, heat pump.

i believe that on both thermostats the fan mode simply turns on the fan in the a/c unit on the roof. i believe that the a/c mode turns on the fan and the a/c on the roof. when in a/c mode each a/c runs independently. in other words you could set the front thermostat to one temperature and it would cycle the front a/c based solely on the temperature the front thermostat senses. it would have no control over the rear a/c and/or rear thermostat and vice versa.

there is only one furnace in the trailer (as best i know). so if you set either thermostat to furnace mode, do they both have the ability to cycle the furnace on and off? in other words, would the furnace turn on based upon a request for either thermostat? also. there appears to be a blower in the furnace that puts some hot air out the furnace registers. but yet when you set the thermostats to furnace mode, the fan in the associated a/c unit starts to blow. i do not believe the furnace output ducting is routed to the roof a/c ducting, or is it? why do the a/c fans turn on in furnace mode? also, i do not see any louvers that you can adjust on the furnace output registers. our furnace is in the wall between the bathroom and the rear bedroom with circular vents in both walls. there is a rectangular vent in the floor in the front living room. needless to say we have the hottest bathroom around and absolutely no hot air making its way to the living area. is this normal?

finally, i was told to use the heat pump mode on the rear thermostat for cooling only. is this correct or will it also supply heat from the a/c mounted on the roof?

thanks