That amount of space is going to make a lot of people, including me, very jealous. However, it does bring one drawback. From what I have read, it will be very easy to start with ambitious plans and then get downhearted at the lack of progress. I would suggest working on a small part of the space at first but work out before how it can be included in a much larger layout. You could plan the whole thing and lay track roughly for much of it but concentrate on making scenic only a small part of it initially.