I live in a condo complex and have a small backyard (17 x 15). My wife and I would like to put down some sod down so it doesn't look so terrible!

The previous owners put flagstone down over some sand and gravel. The gravel is easy to extract, but there is a ton of sand, averaging about 3-6 inches deep. It's going to be tough to get a truck close enough to make the dig practical.

Would it work to put some peat or some other kind of soil down over the sand?

Bumper, where are you located? The answer to your question will be different based on your soil requirements.

I'm in the Denver Metro Area.