Well I have a similar project going on, however mine is based on a pinboard that someone was going to throw away (so it's rather small for a board, but seeing as this is my first boardbuilding project and it was free, I didn't mind). One side was a bit like wood and the other had a sort of white fur/fabric on it (it's hard to describe). So what I did was paint the fabricside green so it resembled grass. On the other side I used grey and added some sand and some tiles made of a cereal box. That side should become an city environment eventually, some osgiliath-like.
If you think the flock will come off, you might want to use a grassmat on one side (and just glue it on). Or you can make small borders on the side (like my pinboard has) or some kind of small rise in the corners so when its turned over, it rests on these corners rather than on the whole board and the flock. I'm sure someone can come up with an idea to camouflage these rises as a hill or rocks or something. But as I said, I'm new to this
But I will take one some time this week end and post it! The table was made so that you could switch the surface from top to bottom and over and under so that you could have four tables in one. It also was a passable piece of furniture.