To make an obvious point, 'hard to get to' does rather depend where you start from, and RCD is about one hour from Belfast, the capital of Northern Ireland, and Dornoch is nowadays an hour from Inverness, the unofficial capital of the Scottish highlands. If you mean 'hard to get to' from the USA, understood! Turning this round, how many storied US clubs and courses are more than an hour from a city of (say) more than 50 000 population? In the UK, Harlech and Aberdovey would both fit the bill, but I can think of very few other courses of similar stature of equivalent remoteness on this side of the Atlantic: of Ran's 148, only perhaps Askernish (which is sui generis in lots of ways anyway).