Yes, flights do go from Glasgow to Campbeltown and back twice a day. It's not the easiest thing to work into flights coming from the US, but it surely can be done. One just has to allow extra time at the front and the back of one's trip. Pretty reasonable prices, also...
As for concrete organizing, well... we need JJSE to come back, this remains his baby. I do stand ready to help in any and all ways from the US travel side, however... and if we do Machrihanish, I believe Darren would be invaluable in helping with the setup...
Remember also that this "official" gathering will just be 3 days, golf-wise. One can easily stretch the trip before and after no sweat. It's a short little flight back to Glasgow, and you go from there.
TH