Great report.

Re "Chugged out through Eustasia Sound - the charter company had asked us not to do that due to the shallow depth, but I wanted to see it"

Your lucky you did not get into trouble in eustasia sound. I have seen many sailboats go aground in there.

How would you explain going aground to the charter company ? The insurance company, and the people who had the boat booked for the next charter?

If the base says it's out of bounds, it's generally prudent seamenship to follow the advice.