Spare tire (inflated), jack, wrench
Jumper cables
Tow strap
Tools - any that she knows how to use and might be useful
Small shovel
Hatchet or saw?
Cell phone
cell phone car charger
Local phone book
Prepaid phone card
Wool blanket
Warm hat, warm gloves, mebbe a good wool sweater
Umbrella or rain jacket
Comfortable walking shoes and socks
Bottled water
Spare food
Wet-naps or hand sanitizer
Toilet paper
Small backpack
$100 cash (small bills)
$5 change (mostly quarters)
Credit Card
Spare keys
Copies of relevant documents (insurance, registration, dirver's license...)
First aid kit stocked with LOTS of the basics (it'll get raided for little things over time, make sure it starts with enough extra so there will still be plenty left for an emergency)
Flashlight, spare batteries
Battery powered radio, spare batteries
Gun! (ammunition, magazines, holster, belt...) (Only if she is competant and willing to use it)
Anything else I've forgotten...