From Annapolis...
... you have lots of choices for single overnight trips. Of course, a lot depends on the weather and wind strength and direction. Being in Annapolis, I assume you've explored the upper reaches of the Severn. Going north, the Magothy offers lots of anchorages, but I'd stay away from behind Dobbins Isl as that's where everyone goes. If the wind is right, you can make it up to Fairlee Creek on the eastern shore. As one poster below noted, you can explore the Chester and Corsica rivers forever as they are grand. If the wind favors going south, head over to the Wye River (and like Dobbins, avoid the popular Shaw Bay) and head up around the "S" bend to either Granary or Dividing Creeks on the north side. Or head across Eastern Bay and drop your hook behind Tilghman Pt, or keep going down to St Mikes and the great anchorages on the other side.... You couldn't be in a better place to cruise from....