So, I noticed that you can't build a campfire inside a cave. The reason I bring this up is because I had a bit of RP going during one of Barovia's particularly harsh winters and the PCs I was interacting with and I had decided that spending the night inside a cave would be smarter than spending it outside in the snow, at the mercy of the wind and cold. Only when we got in there, we realized that we couldn't actually build a fire despite having RPed bringing wood along with us.
I assume that the primary reason for this is that you can't differentiate between a cave and, say, the Lady's Rest? The second reason could be argued that there isn't any firewood inside a cave. So, to address both those points: could we not set certain areas within caves (relatively close to the entrance, I'd imagine) where you can build a campfire if you are carrying wood? I don't imagine it would be too complicated to set up. This way, if you're stuck spending the night outside during a storm you could just try to find a cave and brave the potential dangers within to be a bit warmer.