I'm pretty sure the air hitting the doghouse from a V10 with the AC on is hotter than the air hitting the rear bedroom of a DP.
I rarely have to run my roof air, but there is only two of us and I close the door to the back and leave a roof vent open back there.
As was suggester earlier, you need to make sure the hot water is turned off to the heater and most DO NOT shut all the way off so I added a manual valve to mine. I also removed the cap tube from the evaporator so my compressor never turns off, but in the East after 4-5 hours the air flow will drop off because the evaporator is stating to ice over. Turning the AC off and running the fan on high for 15 minutes will usually melt the ice and your good to go for another 4-5 hours. Out West it rarely ices up because of the lower humidity. These changes let me run only the dash AC on days when it's 100. I do leave two of my AC's turned on so 20 minutes before getting to a CG on a hot day, I start the generator to cool the back of the MH down. If it gets too hot while traveling all I have to do is reach down and start the genny.
I also adjust the amount of freon in my system by making sure 90% of the condenser is 15-20 degrees hotter than the last 10%.