Scouting is everything when it comes to making your life easier.

Set up a bronze base by a shoreline that has four or five copper nodes close to each other. Especially when the shoreline has a lot of little creeks and inlets that dramatically increase the tin in a given area from the increased "shoreline".

That way you can be processing it as you dig it out and not have to worry about a lot of transport.

Why move the mountain to you when you can simply move to the mountain?

It doesn't take a lot of copper to set up a forge and a couple of upgrades so after that you want to look for resources near a copper node you can set up on/around.

That's how I play anyway.