The dry run was a great success. There's enough material to work with between Druid Hill Park and Cylburn Arboretum, which is not far from the park, that we could kill an entire day just there. Jim Shanesy, Diwan Bhathal and I spent the morning shooting at Druid Hill Park. There's a victorian Conservatory in the park, which has some fantastic plants, including a massive Agave plant in the desert conservatory. They have an Orchid room, great for folks into macro or color, and a formal garden outside. Good news for the large format and macro crowd- the Conservatory permits tripods inside. It is also rarely busy, so you don't have to worry too much about the crowds getting in your way or tripping over your tripod.
Within a very short walk from the Conservatory there are several pavilions, monuments to William Wallace and Christopher Columbus, and the lake. The lake has a folly at one end (now closed for safety reasons) made to look like a moorish castle tower, and a stone pumphouse in the middle of the lake with cast iron railings. I'll post some scans when I get some prints made.
Cylburn Arboretum is worth an entire day in itself. The Arboretum is 178 acres of protected parkland in Baltimore City. There is the mansion itself, which is quite photogenic. The mansion grounds have numerous spots worthy of attention - a formal garden, marble lion statues, and acres of greenhouses. There are various trails through the woods marked for the species of trees and other plantlife that can be found. We were fortunate to have some fantastic fog rolling through the grounds that day, and the property lent itself very well to photographing in the fog. I'll have alternate sites mapped out for folks who want to stick to more urban/architectural subjects.