I was finally able to solve this from my Surface RT directly. I followed these steps:
1. In IE10 (desktop mode), click on the Tools icon (Alt+X)
2. Click on F12 developer tools
3. In the window that pops-up, click on Tools
4. Expand the "Change user agent string" tab and select "Apple Safari (iPAD)"
5. Go back to the IE10 window and go to this URL: m.google.com/sync
6. Sign into your google account if you aren't, already.
7. Click on "WindowsMail"
8. In the URL, you will see this string (without the quotes): "supportMultiCalendars=false". Change this to "supportMultiCalendars=true" and reload the page.
9. Now your google calendars will show up. The main google calendar will show up as "My Calendars". The other calendars will show up as "Shared Calendars" and calendars under this option will not be selected.
10. In order to select these "other calendars", disable JavaScript in IE10. Do this by following instructions here (these instructions are for IE9, but apply to IE10 also):
IE9 JavaScript - How to Disable JavaScript In Internet Explorer 9
11. Select the calendars you want to add (I don't remember if I had to refresh the page for the Javascript change to take effect).
12. Click on "Save".
13. Open the Calendar app to make sure your "other Google calendars" now show up in the app.