Jack C and Mark C,
I have to respectfully disagree with your inclusions of the 17th holes at Beverly and Flossmoor. Difficult holes for sure, but TOO hard? Just my opinion, but "too hard" holes are holes where doubles (or higher) or the pocket are relatively commonplace for anyone - OR - there is an aspect of the hole that renders it borderline unplayable.
Let's start with Beverly's 17th. The length, wind exposure, pitch and slope of the green, and flag high or long recoveries provide plenty of difficulty. All provide more than adequate challenge, but none of the above should cause you to completely butcher the hole or not finish. There is also a very conservative approach to the hole in playing your tee shot short or short left of the green which leaves a reasonable opportunity for par and a likely bogey, provided you don't blast your pitch 15 ft. above the hole. Very hard par 3, yes...too hard, not from my POV.
Now, Flossmoor's 17th. Very stout par 4, but by lowering expectations and playing it as a 4.5 or 5 it is certainly manageable. There are no lost ball opportunities. There is the creek crossing the fairway, but that should be easily negotiated unless the hole is playing into the wind and the tee shot is a complete foozle (thank you, Sir Bob Huntley). I grant you, the long approach shot, staring at that near vertical hill is uber-intimidating. However, if you don't make it up you are left with a wedge of some sort to one of the tamer greens on the course. Actually, if you've hit a good drive, and the wind conditions aren't horrid, it could be a wise play to take the slope out of the equation and play well over the green. There is plenty of room and the resulting pitch would be very straight forward. As previously stated, once on or around the green it is one of the least challenging on the course. Personally, I struggle more with the 12th hole, but that is due in large part to the occasional loose tee shot. On 17, you can hit your drive almost anywhere and still have a reasonable chance at a 5. Very, very hard par 4...too hard, not from my POV
Obviously, if I am fortunate enough to play either of these courses again I will skip the 17th holes as karma surely has a bloodbath in store for moi...