For email unless you can get pop access to your various folders (which Google can poll) I am not aware of an elegant solution. Setting up Auto Forward would probably not be allowed in a normal company setting. Beyond that you're probably going to need code.
For calendar, contacts, tasks and notes the solution I found was to use the memotoo platform - http://www.memotoo.com/#sync_website
This combines synchronising to/from just about any address/calendar combinations - some are smoother to set up than others though.
It provides an exchange compatible interface and will sync calendars and contacts to/from Outlook/Windows or Exchange server.
You can set up memotoo to connect as you to your exchange server (warning: your company might not like this happening) as well as sync to google. You can set up directions (always from outlook and out to google, for example, or both ways etc.) and you can limit to certain tags or categories synchronised.
Note: If you had already at some synced manually through export/import, you will risk duplicates happening the first time, which memotoo (and gmail) can then detect and fix, but it is a time waste we dont need. If I had to do it again I would wipe one of the address books to have a cleaner start.