I found this in another thread and it seems to have resolved my iCal Sync to iPhone and iPad calendar issue:Re: I can't sync iCal to iPhone through iTunes in Mountain Lion (I don't want to use iCloud)
Hi people, I think I have a solution:
Quit Calendar, and try removing the cache files from your Macintosh HD/Users/yourusername/Library/Preferences Folder. To find that Library folder, use Finder>Go Menu>Depress the "Option" key>Library. Delete any files with CACHE in their name in the Calendars folder.
When you open iCal again, it says "Updating calendars", and the sync now seems to work.
Of course, do a backup of all calendars before doing any of this.