I have a Mr Buddy (small one) and it keeps my small 25' camper toasty, and with the bedroom up front much of the heat travels up there and we're nice and warm.
I hooked mine up to the low pressure line feeding the campers heater so no small bottles to worry about.
BUT, you still must circulate some heat into the underbelly by running the stock gas heater in conjunction with Mr Buddy in the camper. If not you could wind up with frozen tanks and water lines.
I have been giving some thought to that issue and may install some fans that will direct coach heat down into the basement without the need for running the furnace.
Ron W
03 Dodge 2500 SRW,SB,EC
2018 Keystone 25RES
DRZ-400SM
DL-650