Here are some hiding spots in multiplayer and singleplayer:

Upheaval (The house next to the burning house) - Stand on a windowsill and face the side. You should fall on a ledge below.

Upheaval (The burning house) - Go up the steps and out the window in the same way to hit a ledge below.

Hanger (The porch outside the hanger entrance) - Close to the hanger there is a large white carved stone. Jump on it and try and hop over the fence. You'll fail, but you will land on the fence.

Courtyard (At the end of the courtyard) - Go into the shack and turn right. Use the jutting out portion of wall to hop into the tree.