I'm envious of your problem.
I agree with storing everything at the nice studio in the mountain home, and making up kits to take to the "shack". How far apart are the two homes? Depending how many kits it would take for you to get through winter, would you be able to swap them out with ones from the mountain studio occasionally? I live in a pretty small apartment at the moment, and I'm finding it challenging having my extra supplies crowding me, so depending how you work, it might be nice to only have a couple kits at the waterfront place, and then pick up new ones when you're done the first ones.
Another idea to consider: hire/adopt me to look after the mountain home in the off season, and curate your quilt/fabric collection. Whatever bits you don't like to do, I'll take care of... ironing? cutting? squaring up blocks? I could even deliver kits to you at the shore when you need them. Maybe not what you were thinking, but do keep it in mind.