Bill,
The answer is pretty simple. If this is your only round at Old Mac, miss your plane before missing this golf course - but you're going to have to hustle my friend. You can buzz around Bandon or Pac Dunes very quickly - particularly if the wind is not a factor. You can run around the front side of Old Mac, but the back nine is a lengthy gauntlet.
If you've gotten around it already, I agree that 18 or even 27 on the Preserve is the ticket. Part of the Bandon experience is, well, the experience. Walk off the par-3, have a nice early lunch and be on your way. Maybe I am getting old - but after two and half days playing 90 holes, the last morning is best spent decompressing with a relaxed wander around the Preserve.
And for gawdsakes - especially if you are prone (as I am) to finding yourself a trifle over-served on a buddy trip - make sure you leave the Bunker Bar by 10pm NO MATTER WHAT! There is a strange and unexplainable force field that grows steadily stronger as the witching hour approaches. Once the clock strikes midnight, the metaphorical hatch locks and there is no escape until 2am. Believe me, that wake-up call for a 7:30 tee time (with another to follow at 1:30) is only slightly less painful than hemorrhoid surgery once the anesthetic wears off.