Yes the Hilton does have an underground parking garage, not very good for photos, the only other parking near the hotel is on the street, at meters, which generally is full due to SCAD being right across the park.
Also the Hilton is about 10 blocks from the waterfront and the city market.

I will check around and see what kind of rates I can get and give everyone a list, then you choose which best suits your budget. Probably best bet is for us not to meet up at the hotel but in a central spot for photo opportunity. I will be looking for several locations for us to stage our cars for this.