I know there is an almost infinite amount of travel in this game, but I was just messing around with ender pearls now that they are damage free, and I tried to get above the bedrock layer in the nether. I had obsidian and a flint and steel, so I was fine getting out. But the instant I got above the bedrock layer, it teleported me down. I know from single player that the layer above bedrock in the nether is very useful for minecart travel and for muilfing farms. There is currently also a method to breaking bedrock, with dark oak trees. You could theoretically expand your farm all the way to the maximum build height, or just have a very flat, easy nether rail to get a good 100,000 blocks in the overworld. You can just build an iron golem style gold farm above the roof of the nether and you will not have to deal with slabbing, (trust me, it is NOT FUN AT ALL) pouring lava everywhere, or even just digging out an enourmous area for the spawning pads themselves. I know this may be hard to get out of if you get stuck with no saplings or obsidian, so maybe add a /unstuck that brings you to below the bedrock level like the action that is performed when it says "RETURNING YOU TO A SAFE LOCATION."