http://www.destateparks.com/downloads/maps/cape-henlopen/cape-henlopen-Main-2014.pdf
http://www.lighthouseviewtackle.com/
Saltwater fishing is most productive with bait (shrimp, cut bait, blood worms, etc.). It is not out of the realm of reality to fly fish for saltwater fish and the most effective pattern is a Clouser minnow, Deceiver, or "half and half" pattern. Colors...the sky is the limit.
Flounder are aggressive predators and will gladly take flies. Bluefish, well, they're bluefish and will destroy a fly. Croaker, spot and other fish will also take flies.
Tides play a big part when it comes to successful saltwater fishing. As the tide comes and goes, so do the baitfish which in turn attract the predators. The fish are either there or they're not. It's not like trout fishing where fish have likely "lies". In a saltwater environment that is largely structureless, the fish are nomadic in nature and always on the move, save flounder/fluke who just like to hang out on the bottom.