from what i found you can reload the area by leaving and entering the abandoned town, it takes quite a few tries to even get gin to go to the lake, and even more to get cassie to to go there as well. you can just cycle it. but doing so doesnt progress anything....although once there they dont leave, but cassie also goes looking for apples, so you need to keep going there incase shes there so you can re-roll for her to be at the lake...