What is the best way to organize a Kids Fundraising Event Scavenger Hunt?

We are planning on organizing a fundraiser which would be a scavenger hunt taking place at Fort York in Toronto. The idea is to have the kids and their families attend a fun filled event where they can all be involved and raise money for a non prfit charity. We would be expecting about 1000 kids under the age of 12 and their parents and families. We are hoping to build a list of ideas and resources that will help us brainstorm and plan this event.What is the best way to organize a Kids Fundraising Event Scavenger Hunt?
you create a list of simple things like flower print papertowel and blue magnet red crayon etc. and give it to the children. have them go to houses and ask people for the items. the first to get them all wins.