Mimi, parking is $5 a day payable in advance at the gate. I took the first Galaxy 11 nighter out of Baltimore. Both embarkation and debarkation was a problem. We parked on a pier adjacent to the terminal. Then waited for a bus to pick us and our bags up. The bus was immmediately filled with baggage, so few passengers were accommodated on each trip. When the cruise ended, the scenario was repeated. There were no porters at the parking area, so the elderly had to do it alone.
I understand on the following departures, instead of busses, trucks were used for the baggage. So, perhaps you won't have too much of a problem.