Originally posted by Zep Tepi:

If you don't want to mod, but don't mind server hopping, build your base in one world and do your boss hunting in another. You'll only get the first raid which is just boars and necks. It also gets around the metal transport problem if you mine in another world and come back with a full inventory.

This. You can make a world just for chill relaxation and exploration where you never kill any bosses, and simply transport essential gear to get started for your main world.