RE: Time Off reason in Schedule Board
Step 1:
Create a Reason (option set field) on the Time Off Request Entity
Step 2:
Add Time Off Request as an Entity that can be scheduled

Step 3: Input the settings as below. I've created a new Booking Status of Out of Office for Time Off Requests.

Step 4: update Schedule Board Settings for Time Off request.
I usually do this in the administration area for the scheduled entity. My Booking Template for this entity would look something like this: <div>Time Off - {new_timeoffreason}<br />Duration: <strong class="bold">{duration}</strong></div>
Step 5: Create a workflow. When a Time Off Request is Approved (or the Status = Inactive) create a booking for the resource.
Step 5: When an item is booked, I would see the reason on the schedule board. My environment is going through an upgrade at the moment, so I cannot update my schedule board settings, but below you can see the concept.
