Absolutly this could be done. I went around the Delmava 3 times in a Stiletto 27, which is a 1500-pound cat that can motor about 10 knots when loaded. I ran a good bit of inner passage and some outside. This is what I would do... probably.
* Inside from Lewis to Indian River. Maybe camp there or maybe run on down to Assateague. Maybe I'd run some outside, near the beach, depending on the wave dirrection.
* Inside of Assateague. More interesting than outside anyway. Stay at the Anchor Inn in Chicoteague (free boat tie-up and you'll need the shower).
* Wait for nice weather and run outside to Watchapreage.
* Inside to Cobb Island. Winding but very nice. Awsome. Camp somewhere.
* Inside to Cape Charles. There is a ramp on the VIP near the sothern end.
Lots of fuel. Cell phone, VHF, and perhaps SPOT. Oars. Camping gear. And a sense of adventure. At least do the southern part of the trip; it is once-in-lifetime beautiful inside.
Sail Delmarva: Trip Report - 2010 Delmarva Circumnavigation
I never ran the inside portion from Chincoteague to Watchapreague as I had been told it came and went.