Basement access door under the nightstand.

[ScottyGS]

I set my cube heater on the kitchen counter with a cutting board underneath.  Even when it gets hot the bottom of it is cool enough that I probably could put it right on the counter.  But why take a chance. 

[SeaDawg]

Like Topgun2, we place the portable heater on the floor, not on a rug. We feel it does a better job than on the counter or table. 

I would not leave any portable heater running when not in the trailer.