There is a parking garage next to the Aquarium (a great take for families) which is next to the dock where you get the ferry to Salem. It is not inexpensive, but there is a cap (which we hit) of approx. $40 for the 10 hours we were parked. The Salem Trolley Tour (which I also reviewed) meets every ferry that arrives in Salem. It parks right at the head of the dock you will be leaving from. You hop aboard and it takes you about a mile to the main trolley terminal (a sidewalk booth, lol), which is next to the Peabody Essex Museum and basically in the middle of the city. If you choose to, you then purchase tickets for a 90 minute, 8 mile narrated trolley tour. I highly recommend it. At any point on the tour, you can pop off at an historic site that interests you, then get back on any other trolley that comes by later. You just wave your blue ticket in the air and the driver will stop for you. The trolley ticket is a bargain at $18 for adults and allows unlimited travel. (Same trolley in Boston costs around $41 and $34 in Key West.) If you choose to pass on the trolley, turn left when you leave the dock, you will pass several points of historic interest and arrive at Pickering Wharf which has great restaurants and neat little shops. But the trolley will take you there also. Whatever you decide, have a wonderful time in Salem. Getting there on the ferry is half the fun.