Hi PersistantPuppy. Did you ever decide to crate Molly? That's what I would do since she's still having anxiety when you leave.
The negative to not crating her is that she may just substitute the wall eating for something else that is destructive (if her behavior is caused by separation anxiety). If you do a search on the forum there's a lot of info on SA. Although there is the possibility that your dog is doing it because she wants to chew something or is bored.
If you crate & work on the anxiety you can stop crating her once she gains more confidence. The older my "pup" gets the less I crate her. Right now she is only crated when I leave for long periods of time. Soon I'll test her out on even that. Right now she seems to take the time to nap since I try to wear out before hand. I see crating as a tool to use as they're learning, not as a means to an end.
ANother idea is spraying the wall with something like bitter spray. They also sell a product that is similar to the invisible fence but meant to be used to keep a dog away from a certain area. The one i seen is called "PetSafe Pawz Away Instant Pet Barrier". There may be different ones to look into.
The best thing would be to teach her while she's in the act, that it's unwanted behavior. But if she's not chewing on the walls while you're around you can't teach her not to do it.
Maybe someone else will have different ideas since I'm very pro-crate. Good luck again!