I'm the Annapolis SSCA Cruising Station. If you are a member look me up and I'll help any way that I can. I live on Back Creek.
Any street in the City of Annapolis that ends at the water has a free City dinghy dock.
There is a dinghy dock right at the show, so you can anchor pretty much anywhere. Note that the anchoring restriction off the Academy wall is now being enforced more than previously. I know the pump out boat won't serve you there. I think the water taxi doesn't go there either. The holding is better in the South Anchorage and it isn't really any further away.
If the downtown restaurants are you greatest interest anchoring in the South Anchorage or up Spa Creek will be most convenient.
If local services (grocery, chandleries, hardware, propane, etc) are important Back Creek is a better location.
You're going to find most marinas are booked by now.