It was stated in part 1 that you need the sharingam or rinnegan to open the door to the uchiha shrine. maybe it's that shrine then...Where did you get this idea?
They stopped because Chocho wanted to. Salad just made up an excuse to keep going and find Sasuke.
That's not the shrine. The Naka shrine is inside Konoha, in the old Uchiha neighborhood. It was destroyed during the Pain assault.It was stated in part 1 that you need the sharingam or rinnegan to open the door to the uchiha shrine. maybe it's that shrine then...