Hey, you don't have to hike on this
The story on Amped 3 is bizarre at best. A tongue in cheek adventure that added pretty much nothing to the game except filler. Thankfully the game is not based too much around that other then unlocking the new mountains. When you get tired of shredding, you have the option to bomb around the mountain on a mired of sleds or snowmobile.
One nice feature to mention is the snowmobile, if you overshoot your mark for an event on the mountain, it is not a complete pain to get back to where you are going. The challenges are just that, and will test you on all vehicles, air, jib, spins, and even carving.
Now the game is usually found in the discount bin or as a rental, I definitely say its worth checking out if you are looking to spend some time this winter shredding on your 360 waiting for stoked to be released.