So, I went on my local server and butchered it with far lands visits. I teleported to the bottom of the world, and it worked just fine. I teleported to the corner of the world, and the map loaded but crashed a second later. I teleported to the corner again, and it worked fine again. Maybe it's because the map was already generated, but teleporting way outside of where the world generates worked, and going to the corner of the world never worked no matter how many times I tried in multiplayer (jordan's server). Anyways, here is the promised debug.txt:
debug.txt. I posted the entire thing because I had several sessions. If that's too confusing I'll post several shorter files.