I did install the dog door today. Dinah and Alice are old hands paws at it and adapted immediately.
Bess was dubious. She pawed at it tentatively, sat down and whimpered. With much coaxing (verbal and gustatory) and a hand to hold open the flap she went through, but it took most of the day for her to finally come through on her own. The last straw was seeing KJ tossing the ball for Dinah in the backyard. Whatever it takes...