All of the courses we've played were extremely challenging; much more challenging than courses in and around Calgary. What they call "rough" in Scotland is actually rough (purple heather & long fesque) not a fairway with longer trimmed grass. One of our foursomes did win the lottery to play the Old Course at St.Andrews (you have to win it to be guaranteed a tee time). But the other foursome that didn't win that morning, went to the starter booth, waited in line and got in on the cancellation list, so it wasn't too bad. If you can, try playing the Old Course; it's so beautiful and so historic, and so unusual to play - with tourists just walking around the course and gazing at you; one of the tee shots has to be made over a hotel roof
You will need a letter from some (any) golf course confirming your HC at 20 or above. They don't really care if you play bad, honestly. Beware, caddies are mandatory, snotty and expensive over there.
Kingsbarns was by far the most majestic golf course in terms of views out of 8; but really, they are all beautiful. It was easy to get a tee time there.
Most of the big-name distilleries in Scotland have been commercialized to a degree that it's like walking into a boutique store (i.e. Ardbeg). If you like Scotch and want to see the old production process, Isle of Islay has Bowmore, Laphroaig and Lagavulin distilleries - they are all great (Bowmore being the most educational, Laphroaig being the most generous in terms of free sampling after the tour
).
Dinner at Inverbeg Inn on Loch Lomond was spectacular - great meal and beautiful views/atmosphere/service.