It does not get much more difficult going away from spawn. Except there are chances of spawning like draug villages in far away meadows and stuff like that. But there is plenty of calm places too. So you can keep exploring. There will DEFINITELY be swamps plentiful with crypts on your world.

Whether you will explore a new world or old one makes little difference, which is why i'd recommend staying on this one.

I am curious thou, what is your world seed name? (people might start giving you info on where crypts are, so dont say if you dont want that)