I doubt anyone will read this, but if you do then hear me out. In the episode Too Young, Jake's speech at the end seems oddly significant.
"It's not easy, but you have to be persistent. You might have to defeat a demon lord, or warp through several worlds. But once you do, you walk up the wizard stairs, and produce your magic key you got in the water world and unlock the chamber door. Then, you walk right up to the princess, and give her a smooch. ...Does that make sense?"
My personal theory is that this will be part of the plot for a future episode, and perhaps the first Adventure Time TV movie (Up the Wizard Steps). Not only would this be the most epic thing of all time, but it would make the most epic foreshadowing device of all time.