I don't think waiting until a situation happens is the right time to go door-to-door. If you live in a more urban area, perhaps you could introduce the idea of putting together a CERT team at an HOA or other local community meeting. Biggest benefit is that those who wouldn't contribute to post-event effort anyway won't show up for the CERT training in the first place. Those who do will rapidly either prove themselves to be a reliable community resource, or will quickly fade off your “candidate roster”. If you're in the County, I'd suggest starting with the nearest Fire Department or Emergency Management office, they can often be a great facilitator of community involvement efforts towards general emergency preparedness.