I was able to get both my Macs sync'g Outlook 2011 perfectly with iCloud. If the approach I suggested you use isn't right and you want to go the route of Outllook sync'g with iCloud and then all your Apple devices you can do it this way. You'll need Syncmate and since you want to just do Calendars the free version is fine.
Follow the instructions provided by Syncmate to a tee. When i added in my Macbook Air I made a slight mistake and ended up dup'g my records. After recovery, I looked at the instructions again and saw my error. Upon doing a thoroughly clean sync with Syncmate by deleting in my case calendars and contacts and pulling them from icloud ensuring I had a fresh Outlook identity all is going perfect. I set the sync of Calendars for every 30 minutes in sync mate as that's enough and contacts for every 12 hours and I'm thinking that's probably more than is necessary for contacts. The way i did it though assumes your data is all sitting in iCloud.
Since your doing Exchange my feeling there is just to add in an Exchange Activesync identity to Calendars or Busycal. i personally prefer Busycal. i really think this is the approach you should take based on the requirements you specified to me.
You'll be effectively operating multi modal if you do use iCloud calendars for anything. i got the impression you didn't.
So I hope this helps. it does work but just a word of caution if you go the syncmate route. It's very easy to accidentally make a mistake when you're following Syncmates instructions. You'll need to know how to recover from dups if that happens. Otherwise, you'll be good to go this route or with your hosted Exchange server added in to your environment.
