The big key to the whole trip so far will be timing the transit down the Delaware River. From what I can see in the tide tables, it looks like my best bet would be to try to be in Delaware City around July 30. Any sooner, and the tide ebbs too late in the day and I run the risk of hitting pop-up afternoon thunderstorms during the trip across the bay.
Does that sound right so far?
According to 2013 Eldridge Tide and Pilot Book, p. 143, on Tuesday, July 30, 2013, the current turns to the N.W./flood starts at the Delaware Bay entrance at 10:58 a.m. and 11:46 p.m., with a projected speed of 1.8 knots after the a.m. change. The current turns to S.E./ebb starts at 4:26 a.m. and 5:16 p.m., with a projected speed of 1.7 knots.
Adjusting the Delaware Bay entrance to Bulkhead Shoal Channel off Delaware City on p. 28, you add 3 hours and 15 minutes for flood, projected to be 2.1 knots at 308 degrees, and 2 hours and 55 minutes for ebb, projected to be 2.1 knots at 138 degrees.
Consequently, at Delaware City on the 30th, the ebb will start at 7:21 a.m. and flood will start at 2:13 p.m. You probably need to start an hour or 2 before ebb to make maximum speed down the Delaware River and Bay. It appears you have about a 50 n.m. trip from Delaware City to Cape May. You will be fighting an adverse current for some portion of the trip if that is your departure site. You might instead take Chef2sail's frequent advice to anchor at Reedy Island and wait for a favorable current, which puts you that much closer to Cape May for an easier shot.
On Monday, July 29th, p. 151 of Eldridge shows the east flood on the C&D canal at 10:02 a.m. and 11:07 p.m. with a current of 1.9 knots after the a.m. change, and a west ebb at 4:24 a.m. and 4:07 p.m. with a 2.0 knot current after the p.m. change, so you may have a late night transit of the C&D for your best advantage, with a stop at Chesapeake City for rest.
Having transited the Delaware River/Bay to Cape May 6 times now, my only advice is to make maximum speed by motorsailing and spend as little time there as possible. As Schellenberger writes in the classic Cruising the Chesapeake
"Few people cruise the Delaware Bay for pleasure. It is normally something to endure in order to reach the Chesapeake Bay or, conversely, Cape May, in preparation for the Atlantic passage north."
"...if your timing is good you can take advantage of the current to give you a boost either up or down the Delaware Bay. If your vessel can make 6 knots or more, you can ride the current most, if not all, of the way from Cape May to the C&D Canal to maximize the boost and minimize the adverse current, especially in the upper reaches."
Here is my video from last summer capturing the beauty of the Delaware Bay/River area: