My question is, what kind of training is she planning on having? Is she going to be able to take some professional instruction and then be able to carve out some time with her weapon of choice in her busy schedule? I ask that with the fact she is so busy but that she does have small children in the home.
Have you directed her over to Pax's website
http://www.corneredcat.com to read and get some valuable information as well?
I'm a single mom as well with two children and I know what works for me (I ccw on my body at all times a 9mm, I also have another 9mm in a locked gun safe, and I also own an ar15), but without knowing what level of professional training she is willing to take and time she is going to make to get comfortable with her gun, I just can't say which would be the best for her. There are too many variables involved, IMO, especially when it comes to having children in the house.