We made the mistake of going on a weekend, and were told by a volunteer that, on that day, there were two to three times more people than on a typical weekday! So lines were long, and there were people literally everywhere!
Other than that, the museum itself is exemplary. Great exhibits, and really knowledgeable and friendly volunteers, whom I expect are all ex-military.
A great experience, found nowhere else on the west coast. Highly recommended.