If you go 22-0, as you seem to be able to do, there is a good chance you will promote even if you lose in the playoffs (you would need to check the other 63 D4 leagues to see what kind of record the conference leaders have).
The order is pretty much as Underwood described with 1 exception, the first tiebreakers is the position in the conference. So team ranked number 1 will always come before any team ranked number 2, even if he has a worse record (a 14-8 conference leader will be ranked ahead of a 21-1 conference runner up).