Even simple terrain, for RMA map tiles, would be nice - new ones that fit the location better. I'm saying this because I recently had a mission in Antarctica where I had troops advance on a crashed UFO, but not before first going through a convenience store and a barn with a cow inside, all in the middle of nowhere.
For those new to mapping, I'd suggest starting something simple such as a square with a small hill and perhaps a few small items, so that a desert or arctic landscape can use them and have variation without having to have strange structures that don't fit. Not every single RMA map tile has to be an either perfectly clear flat square or some elaborate structure with occupants. I think some more tiles with simple, rolling hills or other terrain would be nice, to be placed around occupied structures.