Actually, "remembering routes" is not exactly an accurate description. It's more like she remembers waypoints. She'll say "I remember this place, we need to turn left here", which of course means we need to turn right.
Like you my short term memory is poor, especially for names. Strangely, though, I have an amazing ability to remember numbers, credit cards, phone numbers, etc. I can quote PI to about 16 decimal places, for what good it does me.