The Bay Guide is the best guide for about any part of the world. Just go and buy it. A year old is OK. Chuck full of a lot of stuff that is all important to Crusing. Anchorages
on the Chesapeake are often a bit complex getting in and out and the Guide does a great job when it's your first time some place. Shallow water
and details are important so a guide in this part of the world is important.
The Potomac is not the easiest place to to travel. Lots of legs with out places to anchor so you need to plan it out. The "middle" part of the Chesapeake is pretty void. The mouth of the Potomac is and can be a very nasty place. We had 30 knots gusting to 40 last fall. That makes a 6 to 8 ft chop about 60 ft in frequency.
On another trip in July it was the only place we sailed well on a 15 day trip was there. So you can get a wild ride at times.
Get a Bay Guide and look at all the places there are and with a decent sense of planning you can make it a great time. Plan for many places and take advatage of favorable winds when you can should you be sailing July and August.
We have friends that stayed at the Capital City Yacht Club (we have reciprocity with them). It's the best!