Yoho, well, you should know about the bird statue on the timeless isle, you use it, it sends you up, and you usualy open 3 boxes.
Yesterday i discovered that you can mount up once you land on the first box, i managed to collect around 6 boxes with the mount,
It WONT allow you to go around wwith the mount, but you can still move much more fast, and reach all the boxes if you use it correctly