Re: Live aboard legal address
When you sign up with St Brendan's Isle, your address will be 411 Walnut Street followed by a box number. I avoided the box number hassles above by instead calling it an apartment. Banks, government entities, credit cards, etc have all been indoctrinated to accept apartment numbers. For example, I'd list my address as 411 Walnut Street. Apt 1234.
I never once had an issue with being rejected because it was a PO box or PMB, and St Brendan's staff never had a problem getting my mail to me. Maybe that trick could help avoid the PO box hassle issues.