If there is one mountain area full of snow and things to do, this is it. Since this is hard to navigate here's how you get through as long as you're done with shopping and upgrading your experience: Go down the slope continuously until you reach Hollow Bones. Go down the icy slide on your left side.
There should be more Nopon merchants at the bottom after you get out of the cold lake. From that point, go right to the Lava Cave which is important a little later. Warp back and go straight ahead to the other side of Jakt Geyser to reach the Sealed Tower. Perhaps at this point it would be a good idea to reveal the rest of the map of this section before going to the Lava Cave and defeating Conflagant Roxeal which is a fire bird. You get the magma rock, warp back and enjoy another cutscene.
When your team is ready to go, unless you really explored the bottom of the map, make your way to Great Glacier for a battle against level 48 Mumkhar. He can be hard is he's the same level as you. But if you have been doing sidequests, battling him would be easy. Also as a spoiler, Mumkhar is Metal Face! After your battle, Egil comes down to get Fiora and Mumkhar. Make the last leg of your journey which is west where the entrance of Sword Valley is. Get ready for more Mechon rampage!