This world is my first Minecraft world that I'm publishing on this site. Basically if you try to load this world, you'll get attacked from all sides by slimes in a superflat region. However, the rest of the world is a default world. This means you have some extremely high cliffs to climb. At the center of the flat region is an iron farm which will provide a constant supply of iron as long as the villagers are not killed. I also planted a few trees near there to help provide wood to make tools when you first get started.
Since the rest of the world is really a default world, it should be entirely possible to access the end and the nether to earn all the achievements.
If you try this world, please comment and let me know what you think!