Tom:
I wish I had made that drive that recently! Family and a new position at work have kept me in trip planning (wishing) mode.
I agree completely - the stretch from Lahinch to Waterville is very reasonable and would keep one plenty busy:
Lahinch - Old & Castle
Doonbeg
Ballybunion - Old & Cashen
Tralee
Ceann Sibeal
Dooks
Waterville
And that's not counting the parkland courses - Adare Manor, Dromoland, etc.
My thought was that it's a pretty good hike over to Old Head from the rest of these SW courses. Because of the drive and time involved, ideally one would stay and play Old Head a couple of times - if the course/experience warranted such an outlay.
En route from Waterville to Old Head:
Andy