We stopped here on our annual national parks trip- this time to the East Coast. We always buy the national parks recreation passport which allows you to get into all of the national parks for a full year for one price. If you are visiting multiple national parks you should look into it because it will save you money, often paying for itself after only two or three stops.
The current visitor center is located downtown at the museum, not by the harbor as it used to be as it is closed for renovation. Also their hours were not correct in my visitor book- they are 10-4 M-F and 9-5 on Weekends. The museum is nice- we did not view the film because we were pressed for time. The harbor is beautiful and the ship that is sitting in it very large. The plaques by the harbor make the visit worth it even if you cant tour the boat because it explains how the harbor worked and how important it was to the area. I would make a stop if you are in Salem.