We are currently working on the same thing.  Our plan at this point is to use an existing event that triggers when a shipment is marked delivered and to see if we can attach the delivery note. The existing event does list the carrier and tracking number and the delivery note would have the rest of the information 

Should be fairly straightforward to build an event on that Tracking Number field when it changes from empty to actually having a value, and then emailing to one of the Comm Methods defined for that connected customer.

You might want to define a specific Comm Method for emails just to be used for these freight tracking notifications, or just use an email that you already have that would work, but either way it should be manageable.  Worst case, if you can’t figure out how to pull the required customer email address directly from the shipment, you could develop a custom field to pull an email (and even allow direct entry in the shipment screen if you wanted to e.g. if you do one-time shipments to customers) into the Shipment, and then call that CF for the email destination.

There are system events related to the Freight Integration status changes, including when it goes to status ‘Completed’. This is a good event to indicate tracking data is now available for the Freight Transaction. Retrieving customer email, etc. is still required in the event action.

Events included with Freight Integration: