Hi I know how to do this i'll tell you the full thing.

1) Pick up the map on the table in the library
2) Go to the room next to your bedroom I think it's the student centre and talk to Patrick he'll give you the next part of map
3) Speak to Keiw by the exit and she'll give you another map
4) Follow the first map to the meeting place with the green line and pick up the note on the floor
5) Follow the map to the shack but instead of going strait there go on the path to your left just before you cross the second bridge (I think it's second) and take the right path when there's a junxion. Ride behind the tree at the top and collect the shovel.
6) Look on the shack map and follow the map to the little island in the middleish left of the map (you'll see) in front of the big tree there's a brownish lump get of your horse and dig it up with your shovel. It'll be the crank.
7) Now go to the shack and put the crank on the well.
8) Now this is hard to explain, i'll try my best. Turn around from the well and keep going on strait untill you reach a junxtion of three roads go ahead on the turn of browny one that isn't main and take the left. Go up to the tree and use the stone you got from the well in the hole in the trunk. You'll get a key.
9) Go back to the village and go through the arch next to the centre where Patrick is. Take the second to last plank and use the key. At the back of the room there is a lamp, pick it up.
10) Ok. Go out of the village and look at the shack map. The turn off in the middle of the map is where you're heading, or in clearer ways, strait on, third left. You should come to a dark enrance.
11) Go towards it and use your lamp. Get back on your horse and ride through. TA DAA!!!!

I hope I helped you and are not too late. I'm just on the next mission and are really stuck if you find out how to do it please post it here and i'll probably come accross it.

Enjoy!

Lydia

xxx