We have a 9,000btu Mr. Buddy. I removed the pressure regulator and attached a 12' hose with a LP approved quick disconnect. I tapped into the LP system so I could use the on-board LP system instead of the small bottles.
We have dry camped for almost 10 years with our Mr. Buddy. With the M/H we put it in the bath room, crack a ceiling vent about a inch. If we want to move air around while dry camping we have a small 12vdc fan, looks like a 12" box fan made by Fantastic Fan, on low it draws like 1 amp vs the 12 amps of the built in furnace.
No noise, and no wasted heat out the side of the M/H with the ducted furnace. It has a O2 sensor and we have a CO detector in the bed room.
It works for us.