I don't understand why people want to be at a "10min run" from iron and copper.

These are not renewable resources. You built your base not too far from 3 crypts and then what? Once emptied that's it, there is nothing else. Same with copper, but this one is so plentiful it's not even a question.

Just pick a nice spot with an harbor and if you need iron, find a swamp, load 16 stacks on your ship and go home.

Being close to things only matters when you enter the bronze age since you don't have a boat.