The ACA Atlantic Coast route will get you from Phila up to Poughkeepsie:

http://www.adventurecycling.org/rout...anticcoast.cfm

The Erie Canal will get you from Albany to Niagara Falls:

http://www.ptny.org/canaltour/

and it is easy enough to get from Poughkeepsie to Albany - I can give you tips on that little chunk if necessary.