Last year I did the James River from Richmond, Virginia to Portsmouth. A two night, approximately hundred mile trip.
http://www.youtube.com/user/dogslife23452#p/u/28/f0GGzPtA3CU
The tidal range on this river can be up to four feet. This is some of the highest tides on the Chesapeake. When coming in it can run a couple of knots against you. After Walkerton Bridge eight miles down, the river opens up slightly. The tree lined banks fall back and open up to mashes. The Fall is a ideal time to view flocks of migrating birds.
At West Point, 32 nautical miles down, the Mattoponi merges with the Pamunkey river to form the wide York River. The south side of the York has high banks and bluffs. At low tide the shore line can be hard to approach due to the 1-2 foot water depth. After the York River State Park you can not land due to a number of Military Camps and Reservations.
On the other hand, the North side of the York River has large marshes. There are some Oyster beds shown on the nautical charts. The main channel does run closer and there may be a few small places to take out for a night camp. Google Earth is a great tool. But, it can be a little deceiving. Areas that look like sandy beaches can be under water at high tide. I might take a day trip and put in at the state park boat ramp to scope out this part of the river. Hugging the North bank is not only the most direct route but also the safest to keep you out of restricted areas.
My schedule is pretty tight. Trying to coordinate this trip with others might put me close to Thanksgiving. By that time much of the leaves will be gone and the weather will be cold, well into the 30's at night.