Mike,
I've played Dunaverty twice and the quirk factor is very high but very enjoyable, Early in the front nine there is a bath tub par three that is alone worth the price of the green fee. There is quite a bit of elevation change and I remember huffing and puffing to an elevated tee on the back nine and being hit by a gust of wind just I arrived at the teeing ground. I wa glad to have the driver to use as walking stick. Lots of wind at Dunaverty and highly recommended. I also managed to play Macrahanish twice and would like to return as I've bailed far right on both of my tee shots on the first.
In 2015 I did make the pilgrimage to Islay to play the Machrie while it was in the throes of renovation to remove many of the blind shots and make it more hospitable to the modern mind set. I don't know how that has turned out, but I'm certain it's worth the trip to play a couple of times.
I tried to play Shiskine last year but didn't get through the round as I was trailing a group of resort/beginners who knew neither golf nor etiquette and after requiring nearly an hour to play two holes I went around them to play the final two holes. There is some nice stuff there and I would have liked to have see all of it. There are half a dozen lesser courses on Arran and I intended to touch on some of them after returning to Shiskine, but a car accident required us to decamp to the mainland two days early and I didn't realize my plans.
Never played Mac Dunes, but I did manage to find my way to the little nine hole course on Gigha (God's Island) just off the west coast of the Mull of Kintyre. I have a write up somewhere???
I'd second Marty that Campbeltown and the Mull of Kintyre would make for a glorious BUDA and I would also second that everyone should drive the peninsula at least once. The scenery is glorious.
And I hate to mention it again so soon, Mike but I actually invited you on both of these trips but apparently the invitations, like dreams in front of the Mona Lisa, just lie there and die there.