As Labatt said, there are lots of posts re: this route.
To recap some of the points for you:
1. Be sure to take plenty of time for this trip. Do not try to meet a schedule. You will be traveling in some waters which can be difficult and downright dangerous, even for experienced sailors.
2. The trip up the Chesapeake and through the Canal should not present any special challenges, if you choose your weather. You should time your Canal transit to concide with slack tide or a favorable current. Lots of posts on this point. Be sure to listen carefully to weather reports on the VHF several times each day
, paying particular attention to forecast wind speeds and direction.
3. You do not want to make any portion of the trip against strong winds. So, going up the Chesapeake you do not want strong northerly
winds (anything over 12-15 knots), and going down the Delaware Bay you do not want strong southerly
winds. Going up the Jersey Coast you do not want strong northerly
4. Be sure to have paper charts
onboard for the entire trip, as well as a GPS
. Although it's a bit expensive, I'd be sure to get the Chartkits covering the Chesapeake Bay, the Delaware Bay, and the Atlantic Coast up to New York.
5. Study these charts
carefully before you go, looking for best routes and for places to stop along the way. The Chesapeake has a number of good stopping places; you can stop in two places in the C&D Canal itself, and one just north of the exit of the Canal off the Delaware River. The Delaware River and Bay have very few places to stop, and it's a long way from the Canal exit to Cape May.
6. With a 30' boat, Cape May is a good place to stop over and await good weather before venturing up the Jersey coast. You can go in the "back entrance", which saves a lot of miles, as your mast will fit under the bridge.
7. There are a few stopping places on the Jersey coast. Atlantic City is the easiest and is OK in most weather conditions. Manasquan and Barnegat Bay are OK, too, but can be problematic when the wind kicks up. Sandy Hook is a good spot to stop also, before heading on up the East River.
If you do your homework carefully, and if you really take your time to enjoy the trip and to pick your weather conditions, this can be a great trip. However, it is not a time to "push things a bit". In particular, the three bodies of water you will be traversing can be very nasty: the Chesapeake because it's shallow and has very short steep seas, the Delaware Bay because it has a long fetch for waves to build, is relatively shallow and has few stopping places, and has a lot of commercial ships to stay clear of; and the Jersey coast because it's open ocean, waves can build quickly and create "unsafe" conditions, and there are few good places to duck in to get out of bad conditions.
I would add just one more thing: the Atomic-4 is not known as a particularly reliable engine (to be charitable). Nor is it very strong. You should therefore plan on having to do some portion of the trip under sail alone, and be prepared to do so if the engine should quit on you. Many boats which have not been well maintained have engine trouble once they get into rough water, since debris in the bottom of the tank gets stirred up and sucked into the filters. They may do fine on weekend trips, but when you get into real waves and begin bouncing around a bit things deteriorate quickly.
Hope the trip goes well.