Thank you as always for your thoughtful comments, and for your additional information on Johnson!

I had originally hoped to focus on Pennhurst's architecture but had a change of mind midway through. Now, however, I am thinking I may write a related post in the future along the lines you suggest. I would be interested to see the chronology and philosophies behind plans like the Cottage Plan (and its successive iterations), the Kirkbride Plan, and so forth. Thanks again!