The way into Dimori Valley or Gust Valley once you are in is to follow the trail all the way up to the highest peak at Calydon Village. Once at the top, look for a Bridge that has been collapsed and a Calydon Fortuneteller standing guard. (You will need to kill about 3 or 4 Calydons in the immediate area). The bridge has two large mammoth like tusks as the only remaining structure from the bridge. You will see a landing on the other side slightly below your current elevation. Just glide to it and you are now in an area called Gust Valley. This is home to regular 5 dot level 50 Wind Spirits including Angry, Foul Wind and Howling Wind Spirits. I found a treasure box there but could not open it. There must be a key or quest for it somewhere.
You can also glide back to where you were before from a higher altitude when you are done. Good luck...