Hudson River to Patuxant River
Going up the Delaware Bay to the Canal is about 50 miles, a daylight run as long as you use the current. Be prepared for an ugly piece of brown water with flat scrubby shoreline in the distance. A massive power plant dominates the north shore for much of the trip. However, the Canal and the sights on the Upper Chesapeake are well worth it.
Going outside is easy in good weather. It took me 48 hours from the Statue of Liberty to Norfolk last summer.
If you have a choice, I''d go up the DB and through the Canal.