RE: Crank style Roof lift system requires physical assistance
My first thought is that the cable has jumped off a pulley and is wedged beside it. I recommend that you go to https://www.popupportal.com/, a site for those that own popup campers. There are some very experienced members there.
RE: Over filling
This is a common question asked on a Jayco Facebook group. Many times it is the pressure check valve on the pump especially if the pump hasn't been used for some time. The check valve gets dry and sticks. Pumping some water from the freshwater tank can help to prevent that. That check valve is located on the power input end of the pump.