Philosophy of Nothing World

Make a glass platform as big as you can and wait for the night. Mobs don't spawn on glass. At night, stars will start falling and you can pick them up and make blocks with them. 
Make a mob spawner until you get enough iron (better quests gives you some iron to ease grinding), then make a bucket and a cauldron. 
Put the cauldron anywhere to get some water (after some rain). To get lava, you have to hop into the end portal below the bedrock, and use the Philosopher's Stone on the obsidian to make into lava. The dragon will die upon entering the End. Now you have a cobblestone generator.
You can get wood from the Underworld Dimension from LightningCraft, but it will be a while.