Here's a few videos where I show my first attempt to do a large print of a landscape, and then a smaller print. If you have some experience with WorldEdit and 3D printing, it should be pretty straight forward to follow.
This post is a detailed tutorial on how to use Mineways to export printable stl files for a RepRap or derivative machines. The details are from a large-ish landscape model, but the principle is the same for all types of exports.