My solution takes in a bit of other country's solutions. Keep the mailboxes where they are (why move them? - don't they have squatter's rights by now?), but if you don't want to drive to them, those whose whole life seems to only exist due to HPPOA and mailboxes form a version of the park-and-ride system we see elsewhere. You get a free return ride to your mailbox but must listen to the driver go on and on, sometimes condescendingly, sometimes not if you're lucky, but it's free. Tipping optional. I call it:
"THE HAWAIIAN PARADISE PARK AND HARK RIDE PARK AND MAIL PARK"
"THE HAWAIIAN PARADISE PARK AND HARK RIDE PARK AND MAIL PARK"