I've built a second home away from home (which I happen to like almost more then my first base) at the first swamp site I found. It's connected to the main base with a portal. It has all the necessary workbenches, kiln and a smelter. I have Black Forest right behind me, so I can get tin and copper as well.

I can work the ore right there in my cozy little hut and don't need to bother shipping it elsewhere.

Bonemass itself was quite far away from this location (even much further away from my original base), so I built a third base there as well. Not as elaborate as the second one, but it does the job. Once I'd beaten Bonemass, I just used it to process iron, and then ferry it to my second base.

Luckily, Moder is just a small hop over a sea strait away from the second base. So now I'm building a fourth, much bigger base (actually a tavern) at the foot of the mountain.

It really depends on if you like building. Build at least a small hut that can house your bed and some workbenches, so you can process the ore right where you harvested it. Oh yeah, and connect all of them with portals. You know you want to.