The trader wouldn't be a good place for navigation aids, cause one of the consequences of nomap is there's a good chance you never see the trader...

But to go back to the OP, what boat are you using at the moment? The longboat, while you still need to do the whole sailing thing, can hold a massive amount without any penalty. I just moved house, and after portalling most of my stuff loaded all the metal in my base into the longboat and at 2600 weight it was barely half full. Getting off the beach at the other end was "interesting" though...

So while you may need to travel a while, each trip can carry a *lot*