Theory: Vista Hill is in Bowser's Inside Story

Abstract
Vista Hill is seen in Mario & Luigi: Bowser’s Inside Story (+ Bowser Jr.’s Journey)

Arguments

 * Argument 1: There is a hill in Mario & Luigi Bowser’s Inside Story that gives almost an identical view of Bowser’s Castle to that of Vista Hill.


 * Argument 2: Both hills serve the very same purpose, being a vantage point for Bowser’s Castle. This is used by Bowser, can be used by Mario, and is even used by Fawful, Midbus and the Best Fitness Friends to spy on Bowser’s Castle in Bowser Jr.’s Journey.


 * Argument 3: Both hills have a very similar colour scheme and appearance.