I've been going through all of the posts to try to come up with something to simplify the process. Here goes - (assuming FED rules)

1. Was the contact obstruction? YES/NO
2. If NO, ignore the entire situation
3. If YES, did the runner reach the base he was attempting to achieve? YES/NO. If YES, was he attempting to ADVANCE or RETURN. If ADVANCE, ignore obstruction and result of play stands. If RETURN, award once base past base safely returned to.
If NO, and ADVANCING, award base runner would have achieved. If RETURNING, award one base past base runner was attempting to return to.

I don't know if I can make it any simpler than this. The key question is - "IS THE CONTACT OBSTRUCTION". When you call NO OBSTRUCTION and coach starts after you, don't offer anything other than "THERE WAS NO OBSTRUCTION". No matter what happens, obstruction is a judgment call.