I’ve shot images in that park over every season for over 10 years for good reason, it has a large diverse of public land. (Hint stay away from Marshalls Creek on weekends as traffic can be a nightmare) There is a road the follows the Delaware from Rt 80 in the Gap area north to Bushkill. Keep your eyes open as this has some great area’s and explore side roads.
The main feature for me is not the Water Gap area, although scenic on its own, it’s a little limited, and if you are lazy, or not as mobile it can be a long steep outing. Look at a map of Rt 209 from Bushkill to Milford. This area is the real gem and explore the forest roads coming down off the hills on the west, and also the ravines. The ravines hold a vast number of waterfalls (Some well know and well developed) other much less, but just as beautiful. Also some old growth forests exist (mostly confined to the steep ravines) On the highlands on the western side you can explore on many forest roads and find swamps, meadows, and lakes. All with out the typical Pocono billboards and vacation homes, and most importantly those nasty no trespassing signs. You will also find some other great scenes for photography some you would not expect in a park, but I don’t want to give it all away.
Early to mid October is usual peak. The elevation difference from west to east will change the peak fall times about a week or so. (So shoot the high lands 1st then the low lands turn peak)
Mike