Camp Sites in Milwaukee?

I am going to be taking a weekend trip up to Milwaukee with a group of my friends using this route. We are going to bike there, spend a day in Milwaukee and then bike back on Sunday. This is just supposed to be a fun, enjoyable trip away for a weekend so we were never planning on doing it all in one day. I was wondering if anybody knew of any camp sites close to the trail for us to set up our tents for two nights? Thank you so much.