Somewhere with you or so that you can get ahold of someone that you have given the information to, is a list of all credit cards - numbers and who to call if you loose them one way or another.
I always take a list of medicines, doctors, emergency contacts, and if we are taking grandchildren the following:
1. Power of Attorney or Authorization to take the children where we are taking them, also address medical care.
2. One of their insurance cards or at least a copy of it.
3. Picture ID of the children - if they don't have passports, most states offer a picture ID similar to a drivers license.
4. List of medicines and doctors
5. Phone numbers of parents - home, work, cell, pagers
6. Anything else that may be of importances
I also, make out a detail itinerary including address, phone numbers of timeshares, cell phones, etc., etc., if we fly, flight numbers, schedules, rental car agencies, etc. If we are driving, then our car/van license number, etc. That way if the parents need to get ahold of us in an emergency, they have all the information possible.
There is not such thing as overload with information.