Teleport Access is rewarded to you at the end of every playground. You will be given a triphook, that is your Teleport Access Key for that playground. Once you obtain the key, go to your Estate and drop it into the hopper that corresponds with the playground you earned the key to. You will then be able to teleport to that playground with the simple click of a button. This is super helpful if you go sad and don't want to run all the way back to the playground you went sad at