I've been up in the bay (from Lewes) a few times and once from the Cedar Creek ramp (where I used to launch every weekend in my bait-dunking/bucktail-throwing larger boat days). Part of the problem for a boat my size, which is basically the same as yours, is that the DE Bay chops up pretty quickly as the morning progresses, even when the winds are down. You head out at 6 AM and it's flat calm and by 9 there's a 2 ft chop. In our boats, that translates into a bumpy enough ride to slow you down - and there's a lot of territory to cover out there. It can be a long ride from structure to structure, be it bars, sloughs, reefs or rip-rap around lighthouses. The anchorage, unless you come across some breaking fish, is too deep for flies with the strength of the tidal flow. You might get lucky and come upon some breaking fish while traveling, but as a rule you find yourself moving around a lot more than you do fishing.
For me, the lower bay near Lewes, the various rockpiles near Henlopen and the 8's provide more fishing time and less running-around time.
One note though: There's a lot of territory in the upper bay shallows that I haven't fished with flies yet - around Port Mahon and even on the other side near the Maurice River mouth. I've read good stuff about it, but haven't made time to check it out for myself. Maybe this season...
The only time I have ever seriously thought we were going to swamp in a power boat was in my Dad's trihull out in Delaware Bay. Something about those waters that can be dangerous for a small boat, especially a poorly designed one!