I am looking into the same thing myself now for a couple trailer houses.
What I have basically decided to do is a 3 part heat system.
Keep a normal wood stove
in the main trailer house part as I have had for years now, use it for instant heat like when I have been away for a week or so in winter.
2nd, build on what I refer to as a heat room!
The Rocket heater
would be in there! I think
I have too many worries about weight and space to put the heater and thermal mass in the main trailer. Also I might be a bit worried about fires or over heating in the main trailer since many are a fire trap to start with. Floors are often junk in trailers also.
In the heat room I would have some thermal mass to store heat and probably a dirt floor, also heat water
around under the trailer house to heat floors and through radiators in rooms as needed.
I plan to use some new bought stuff like pex tubing to flow the water, but also allot of old junk. If a person takes the time to really scrap out 1 junk car there is allot of good parts to be had.
Radiator, air conditioner condenser, heater and air cores, so 4 radiators in various sizes. Also at least 2 12V (sometimes 4) fans.
I won't be able to start working on anything for the main house anytime soon. I do however have a 14'x70' trailer with a tip out about 7'x15' which I will be using for a shop for motorcycle work, machine work, and other stuff and and need heat in there soon.
For that trailer at this time I plan to build a quick heat room as I need something now!
My plan fast and dirty is to build a heat room on the corner where the tip out and main trailer walls meet.
This already give me 2 walls! The windows in both walls there are busted, so one I will remove and just leave the bare opening, the other in the tip out wall I will remove the wall section under the window as well as the window, this will give me a nice large door 9nto the heat room.
I figure I will build a dirt floor for the heat room, room about a 7'x8' and using metal siding/roofing I already have.
put the rocket heater about 1-2' lower than the trailer, so I should get a nice convention going, as heat rolls into the trailer through the window and door, the colder air can flow into the room and drop 1' or more to the heater.
The roof of the heat room will be about even with top of door and window frame, just above.
My only real need right now is to heat the motorcycle machine shop area right now so I can work in there on these 4F-28F nights and 30F-40F days! That area will be almost 20'x20' or a bit more.
Putting the rocket heater in the far corner of the heat room made of metal will provide a large enough
distance I won't have to worry about setting the trailer house on fire. Using a dirt floor not much above normal ground level also removes any worries about weight.
Later I can always add thermal mass as needed to store heat and hot water
system to pump heat to the farther rooms when needed which I do not need to heat right now. I could also easily make the heat room larger at anytime if I want more space in there like to store wood
or items I need to make sure do not freeze like my paints and such. With a good large thermal mass I and well insulated room I should be able to build a hot fir for awhile then leave for 2 weeks and never really get below 40F here in the room if I close it off form the rest of the house while gone.
I will probably do basically the same thing to the main trailer house I live in now, but that will be for next year, but I need heat in the shop trailer SOON.
My only big problem is I wanted the shop trailer to look like a normal trailer from the road if anyone see's it while driving by. In summer it will be well hidden, but winter when leaves and brush is gone it can be seen. So I put it in place with the front facing the road to the south, and most my heat will be on North side!
Also I want that 7' foot tip out section as close to ground as I could get it, and the way it is placed I am only 1 foot above ground at the outer end where my motorcycle will be ridden in and out, that works well as I can have a near level ramp if I go out another 6' for the ramp.
There is a bank or hillside to that side where my shop door is, the other side would been about 4'-5' off the ground!
Do to my other needs I did not place it very well for my solar
which are now on the wrong side!
My main house however the 16' ends are at the north and south, and the 70' sides are east and west. Tip Out on the east side. So when I build that heat room I will have a east wall long as I want up to 20' for morning solar
gain, a south wall of about 8'-16' depending how large I built the room.
It will be protected from the North winds by the main houses tip out mostly, and again I will use 2 walls of the main trailer so only have to build mostly 2 walls and the roof and use a lowered dirt floor which would be about 1-2' higher than ground level but still lower than the main trailer floor.
Good convection heat that way.