I'm make a large building and want to make the "yard" on the board.  I plan on making the "yard ahead of time, my question- how much ahead of time can I make it and should I use marshmallow fondant, bought fondant or gumpaste?  It will be pavement and green for the grass (not planning on using BC and the grass tip)  Also on the building, I plan on making windows - not fancy to "stick" on the cake should they be gumpaste or fondant? Thinking about the weight.   This is more less a practice adventure for me - lol

I use MMF or a mix of MMF and store bought for my cake boards...I just don't see the need to cover the cake board in all store bought because MMF is so much cheaper...Unless I have bought a fondant that I dislike, then I use that... as for the windows, I would use Wilton fondant and let it dry...it dries fairly hard when left out.