In Eden 2.0 the "normal" world has a lot of terrain of different types, and there is an invisible wall all the way around the world.
I wanted to make a track that goes all the way around, but the corners were a bit of a challenge.
Here's how to build off the edge.
Find a place you want to build.
Place water on the edge.
Build onto the side of the water.
Remove the first water, then place new water on the new blocks that you just built.
Extend the floor out as far as you want. Then build up or down off of it.
You can use this to place unreachable objects past the edge of the world, or just make a wall around the edge so it doesn't look like you're about to fall off into space.
You can also build out past the corner, it just takes a few more steps.
Saving and reloading works fine. Mine got a little laggy a few times, I tried to figure out whether the lagging was because of the water or something else, but I didn't figure anything out.