Postal codes should be fine... You really don't want to get to detailed but It is a great idea, btw.

A motorcycle brand that I have owned for many years now has an owners club that publishes an annual membership directory. The "Book" comes in handy while touring the countryside. I don't leave home with out it on any extended ride and have met many people from it through out the years.
Physical addresses were never used but telephone numbers and now email addresses sorted by Country, State/Province, City/Postal code are enough to initiate first meets at a local Pub or wherever.