Never too late to learn to crate!
Luna's is a 42 and it is very roomy for her. She's 60 pounds. Since we suspect Molly has a little Newf in her (I think), I would get a 42. It has only one door, I don't need 2.
Honestly, I would get a camera (like D Link or Dropcam) so you can watch her when you're not home, especially with the baby gate jumping incident.