I started today off by adding a bunch of gold collectibles to Nueva Venicia. While I was doing this, I noticed that the final building cluster seemed difficult to climb, so I added some grapple targets and a flying ship, then tested it. The grapple targets are a little difficult to climb, but doable and pretty fun once you've succeeded.
I spent nearly all my time today trying to test this and making small alterations. Each time I made an alteration, I'd go back to test it and fail to even get there at least 5 times. Eventually I got it right though, and immediately had to close shop.