What part of yellow breeches did you fish? I try to stray away from the run which is where a lot of people new to the area get "stuck". Next time your there try heading down to the Allenberry Resort dam waters. Above the dam you'll find some nice dry fly action and directly below has some nice streamer opps. along with nymphing waters as you work your way downstream.
I know you asked about delayed harvest fly-fishing only but really any of the special regulations areas will help you separate yourself from the "sinkers". I'm not sure if your aware or not but PA has another section called delayed harvest artificial lures only which basically the same, in 2003 PA eliminated the DH fly-fishing only regulation. There are 26 delayed harvest fly-fishing only (DHFFO) waters and 51 delayed harvest artificial lures only (DHALO) projects.
Below are links to an amazing interactive map which mark all the special regulation waters by regions:
Southcentral Pennsylvania Special Regulation Trout Streams -
Pennsylvania Fly Fishing - Southcentral Streams - PaFlyFish.com - Blog
Entire State (You have to click on a region (text) below the colored map to view the special reg waters) -
Pennsylvania Fly Fishing - Pennsylvania Trout Streams - PaFlyFish.com - Blog