My instinct would be that, depending on the time of year, you may end up just making your trailer much hotter inside. I love the light as well, but for any off grid camping, extra heat in the summer would be a no-no for me as the A.C only works when you're plugged in. I've also noticed since I'm Fall camping right now (going down near 0 Celcius 32 F some nights) that the bathroom with the skylight is MUCH colder than the main room in the morning. Could be because of the location of the heater (under stove top) but I'd be afraid up here in Canada of cutting a hole in the roof and somehow lessening the strength of the roof for snow load. For this winter I've found some indoor storage, but may not be able to keep that up in the long haul, but figured it was worth it for my first winter, given the 'quirks' I've found in the trailer so far.
2006 FF Cruiser-X 18'9" FBR
Honda Pilot Touring Edition
"You miss 100% of the shots you donít take"