We wanted to use the deck, at least, soooo we're going to use something the contractors have been using to block off the backyard (since they took our side fence down) to block off the dirt. We'll attach it to the deck "posts" so it'll act as a barrier.
Obviously, the parents will have to supervise, too! They're all well aware of my yard problems :)
Anyway, we happen to have a huge playroom inside and a family room, so there will be lots of space now.