
Originally Posted by baeuchlein
AFAIK, the bank is located to the northwest of the building in which the mission starts. To go there, you can first jump over the gap between the southwest corner of this "starter building" in the direction of the house to the south. Archers should be patrolling there.
Now, work your way to the west until you reach the library. Once there, go to the north end of the roof before the library. You should be able to jump onto a slanted roof there. Go to the chimney on the roof and examine the upper edge of the wall of the building to the west. There should be something wooden there which is ideal for a rope arrow. Shoot one, then jump at the rope and climb up. Be careful when mantling over the edge, as there is a guard up there. When he has passed by, mantle onto the roof, give the guard a standard blackjack greeting on the back of his head

, and proceed to the north end of the roof area.
You should be able to jump at the corner of another slanted roof. Climb up onto the wall that serves as a railing here and try to jump somewhat diagonally at the roof's southeastern corner, then mantle up. This can be a bit tricky. Once you're up there, the bank should be the building to the north of this roof, and you should be able to jump and mantle onto a ledge on the wall.
A partially open window to the east of where you climb up should attract any thief, especially since it's the way into the bank and its riches. Save your game before trying to climb into the window, as it may happen that you are somehow propelled into the air by some kind of bug, and once you hit the ground again, Garrett will either be dead or in need of some emergency medical service.