This is a good challenge. She needs something tough, probably reasonably light, and warm. Or at least adaptable to be warm.
Merrell makes a cold-weather boot called the Thermo Pathfinder ($125; www.merrellboot.com), which is a tough, insulated boot that is also waterproof. Yet theyre fairly light and would work as an everyday shoe for walking around town, wearing in a classroom (will she be teaching?), that sort of thing. Its available in womens sizes.
An alternative is a quality leather hiking boot such as Montrails Solitude II ($140; www.montrail.com). For warmth, she can wear wool socks such as SmartWool Light Hikers ($16; www.smartwool.com) and perhaps supplement those with vapor barrier liners, which are waterproof sock liners that reduce evaporation from sweat, keeping the feet warmer. There are several brands available, and most are around $25 (note: she should change into dry socks every day when wearing a vapor barrier sock, otherwise she might get trench foot").
Also, several companies make good-quality, durable, low-top shoes that are less like a hiking boot. But, alas, theyre mostly for men. Timberlands Classic Trekker ($140; www.timberland.com) is one such shoeall leather, with a Gore-Tex liner, supportive steel shank, and grippy leather soles.
Hope this helps!