I'd like to be able to just have the single shared folder appear in Windows explorer, but somehow the folder + my users home folder (which essentially allows you into the whole machine) is visible.
In System Preferences -> Sharing -> File Sharing, choose the folder that you want to share. In that list, there should not be an entire users folder. In Windows, connect to your computer as a Guest, which will allow you to see what is publicly available. Do not log in with your username. If you connect with your username, you will see your entire home folder.