I can only think of 1 or 2 holes that are a royal pain in the ... From the longs at rolling but I wouldn't use that to say that its the hardest course. 2 of the long tees I love 10 and 11? big up hill strait shot then the following downhill dog leg right. Even if I'm playing the short tees I want to play these 2 from the longs.
Rolling Hills longs, I think I have only ever played once. Didn't seem so bad. Kennsington Black Locust is pretty difficult for 27 from the longs. Oh I just remembered we played Hudson Mills Monster from long tees to all the Championship pins on the holes that had them and that was tough too.
Toughest to date for me was Fly Boy Aviation's private 27 hole course in Georgia, only played it once before hard rains came but it felt like 50+ 'normal' holes. Lots of long holes (including an 1600'+ and several 900'+) and a bit of elevation changes.
I do appreciate a good challenge, but one thing I cannot stand on a disc golf course is when there is no fairway. An example would be a mass of trees that are all 5' apart and 100' off the tee. Really then you're just playing plinko hoping to get lucky. But in the end all you get is Bob BARKer.