Another thing to consider is your knowledge of how large flying operations work. Your Alternate may be 1 hour away, but that doesn't mean there isn't a suitable field 20 minutes away...it just might not have your airline's fuel contract or doesn't have your tow bar or it could be a MIL field, or maybe such a field didn't meet FAA FILING requirements, but would be more than legal to land at...just another wrinkle to add.