Keep in mind that the geometry of this style of comfort bike is all wrong for trails. They sit you very upright, and behind the pedals. In short, bad for technical sections because it steers like a Mack truck, and bad for delivering power to the pedals because they are more forward than on a mountain bike. We sell a similar model, the Trek Navigator, at my shop and getting out of the saddle sucks on that bike as you feel forced into the seat by the bike.
But yeah, try her out on simple non technical stuff with the Sedona before you drop the cash on a nice mountain bike that she might never use. Save that cash for your own parts.