Found a great swamp Island which has 18 crypts on it, I first build a little shelter and portal on top each one so no problems with my shelter & chests getting attacked, so when I clear the crypts of iron I store them on top of the crypt and then move to next, once all the crypts were done I used the hoe to make levelled path between them all, with leveled paths done I can then easily transport all the iron with cart to also a secure port area where I've got 6 furnaces to smelt the lot so the iron is ready for transport on my longship to anyone of by base's, I've iron for days! And I love it!