It may be too late for this kind of thing but here's what I know about it.

Never, ever buy a house on a flood plain, even if it hasn't flooded for 50 years Check out the availability and quality of emergency services - fire, ambulance, and police. Some places don't really have any. I met someone who lived so far back in the hills that the sheriff said they were better off shooting a threatening intruder and calling the police later. ( It's 45 minutes off the highway.) You mentioned children: how are the schools and transportation to them?

I once heard of two families living in the same large house.....happily.....for many years.

Good luck to you.