you have to write down the order of the buttons to push. numbering them laft to right 1-6. granny goes from right to left: 1, 3, 5, 6, 4, 2 then in the reverse on the way back across. Remember that you just have to get to the last bridge and then drop into the pink transporter (or whatever you call it) and it will bring you to the top. if you do it right there is plenty of time. You weren't trying to go up the elevator, were you?
after she goes back to the top and unlocks, then she opens the blue light and lets the other granny access the transporter on the bottom and she goes up top.
have one of them jump down and get the kitties in the levels and bring them up to the top via the elevator.