I was able to connect to my Nexus 7 as an FTP file server on my home network. There are several steps, but hopefully I can explain them well.
First, you need a file explorer program on your Nexus 7. The one I use is the free "ES File Explorer File Manager." It includes a utility for making the tablet an FTP server.
Once ES File Explorer is installed, turn on the tablet's WiFi to connect to your network. Open the ES File Explorer's main menu, expand the 'Network' group, and tap 'Remote Manager.' You should see a screen that shows the tablet's FTP address like this:
ftp://xxx.xxx.x.x:xxxx
From this same screen, activate the FTP function by tapping the "Turn on" button. (To get to this function more quickly in the future, tap the little 'Settings' icon at the bottom and click the "Create shortcut" option on the next screen. This will place a shortcut on your home screen.)
Now you have to create a new network place on your PC. Open "This PC" to show your Folders, Devices & drives, and Network locations. If you don't see a Network locations group, it's okay because we have to add at least one for it to show up.
Right-click in the window's blank space and select "Add a network location." Click NEXT, select "Choose a custom network location", and under "Internet or network address" type the FTP address you saw on your tablet, i.e. "ftp://xxx.xxx.x.x:xxxx" (Without the quotes.)
Click NEXT, check the box for "Log on anonymously", click NEXT, and give the link a friendly name like "Nexus 7" and click NEXT. When you click FINISH, a file explorer window should appear showing the file structure of your Nexus 7.