Encourage her to go out and test ride bikes. If you'll overwhelm her, let her go out alone. The main thing is to get her out and on long enough test rides that she can really figure out what she liked. Make sure she knows that a bike shouldn't hurt... a lot of women get overwhelmed with the gearhead stuff and are used to sports sucking and being painful, so they assume bikes have to hurt too.
If she's got short legs (30" inseam or less), she may find 26" wheels work better fit wise. If she's got really short legs (28" inseam or less), 26" wheels are almost a must. If she's got longer legs, wheel size doesn't really matter. (also, if a broken spoke or tire emergency will freak her out, 26" wheels might be better... they're a smidge stronger and the tires tend to be sturdy)
If she's nervous about weird handlebars, encourage her to try them. I learned a ton from trying as many weird bars as I could, and I am a lot happier with my bike as a result... and I know exactly what bars I'd swap to if I could. (current bars are fairly nice, but not perfect)
For hauling, you want low gears (and so does she). Show her Sheldon Brown's gear calculator and have her play around with it once she's narrowed it down to a few favorite bikes. A 20" low is not too low for hauling a real load up hill. If her joints are at all fussy, really push for lower gears. They do help, even if she's prone to mashing. If she's got plenty of low gears, it will be easier for her to want to ride.
FWIW, I have a Breezer Villager and love it to death. Cushy tires, lights so I can be seen even in bad weather, fenders so rain is no big deal... and for me it is just right for longish rides. But everyone's body is different, and a Breezer might not suit her.