Just re-did a Google search, and this site almost gets us where we need it to go, but it's still not possible for me to select multiple calendars after making them show up:
Teens Into Tech: How To Add Multiple Google Calenders To Your Window 8 Calender
1. Add you Google account to Windows 8. You can do this from the calender settings. Your main Google Calender should now show in the calender app.
2. Now for the hard part of change the calender settings. If you have a smartphone, go to your smartphone's web browser and type in m.google.com/sync. If you do not have a smartphone, you can use this Chrome add-on to trick the page into thinking you're using a mobile browser. If you do use User Switcher Agent in Chrome, change its settings to Windows Phone.
3. You should now be on the Google Sync page. Select the Windows Mail option.
4. In the URL, there should be a part that says "supportMultipleCalenders=false". Change the word false to true.
5. Now, reload the page. Once it has reloaded, there should now be a list of calenders below the mail settings. Select all the calenders you want to add to your calender in Windows 8 and hit save.
6. Reload you Windows Calender app, and all your calenders will now show up!