The portable buddy is a great heater, aside from the condensation issues of propane, and the fact that it has no fan, so you don't get heated air moved around much.
I have found that for condensation sake, as well as safety sake, leaving the MFG recommended ventilation open alleviates the issues. Mostly. Condensation IS a huge problem with propane for sure, but you can vent most of it out.
So that leaves us with moving the heated air. I tried using a battery powered fan in front of hte heater, far enough away that the heat wouldn't damage the fan and it was pointless.
I didn't give up though, and came across the idea to use a heat powered wood stove fan, rigged to hang off the top of the grate of hte buddy heater to move the heated air throughout hte space. Now in my testing admittedly I was heating an already technically warmed / air conditioned space, but I was able to feel a rapid temp increase in the room in less than 2 minutes of running it. And the hold down rig was super simple.
I may try this out on the Coleman heaters too. At least the flat top models as they would be perfect to set one of these fans on...
So now, going into the winter, which is forecast to be freakishly cold for us again this year, we are ready for whatever the weather hands us...
If the youtube link didn't work, here is the URL, I give some reasonable close ups of how I set up the rig.
https://youtu.be/B_1YeNsvV80