I walk about 3000 steps a day and at the peak of this trip, i made 26000 steps. In a day. It was tough... But when you reach the hut and you take a cold shower and your feet start feeling ok again, you can't think anything but "wow, that was incredible". It's so beautiful... Just don't feed the beach chickens.
If you want to train for this, just walk stairs, like all the stairs. With weights in your hands.