I don't notice it so much vacation boat diving but local diving on shore/beaches has given me a good workout. Schlepping tanks and gear to and from storage and up stairs or to the car (apartment living) then from car to beach then back again to dive shop then home, etc....my arms, core, back, legs, everything is a workout. Long surface swims....
I let Mr OOO help out whenever he can (I love chivalry and have no problem playing damsel in distress, haha) but I'm also a DM candidate so gear schlepping for self, instructor, and students is a big part of my gig on the weekends.
I did purchase a collapsible wagon which has helped immensely (and is awesome for Costco and grocery runs when I unload the car). It has received the eye of envy from many and our group has quite a few wagons now.
it makes it slightly easier.