Backyard Help

When we moved in to our house, you could tell someone who had previously lived here was an excellent gardner. There were remnants of flower beds and boxes in every corner. There were also two fruit trees. The all of these areas were ignored by at least two owners prior to us. We tried to recover them all and worked on restoring them for the first few years we lived here. After a while because of having more children among other things, it was just too much to keep up. The fruit trees were dying so we cut them down last year. Most of the flower beds were weed infested, so I've removed almost all of them.

This is the northwest corner of our backyard. It was a very nice raised area with flowers and an apple tree when we moved in. Since then, it has become infested with weed trees, and most of the flowers died off too. We took down the tree last year. The wood that held it up is rotting, so we need to redo the entire area, we just don't know what we want to do. We are open to all ideas. As you can see in the picture, there is a sandbox in the foreground that we built about 5 years ago. The boys didn't ever use it much, but now my girls love it and are in it all the time. Because it is behind the shed, it gets some sun, and some shade. Whatever we decide to do is going to be a lot of work, but it's time to do something. Some of the ideas we've had are: garden area, build a playhouse, blend it in with the rest of the yard. What do you suggest?