Hi Karen,
We actually started off with Workfront in almost the same manner (in the Marketing department of a college), though we were not expecting to roll the tool out to anyone else.
We had our portfolio structure set up differently than you do, which was helpful when we moved into an enterprise capacity.
Our Portfolio was the larger unit (in our case Marketing and Enrollment, in your case it would be Alumni Affairs & Development).
Our Program was the smaller department withing that Unit (for us - Marketing -our heavy users, Admissions, Financial Aid, and Operations).
Now our structure is elevated to a slightly higher level, partially due to the Operations team becoming an Enterprise resource and partially due to a college-wide restructure that we had over the summer.
Our Portfolio is now a higher level - Office of the President and Strategic Enrollment Management.
Under the Office of the President we have several Programs: Enterprise Operations, Marketing, Communications, and Analytics and Decision Support. Under Strategic Enrollment Management we have Admissions and Financial Aid.
We use Companies to identify who within the college our customer is, which is apparently different from how everyone else uses Companies.
For Marketing we have campaigns and events set up as projects and are identified in the name of the project. We also include a 3 letter code for the unit that the project is serving. The rest of the units have a far smaller number of projects that we work on so it's easier to remember which ones are campaigns or events, but we would also include this information in the Project Description.
I hope you find this information helpful!!
~Mini