There is a private golf club with a hill made for sledding right off the main road in town with an ample parking field. While they have never officially "invited" the public to sled on their hill, it has been the de-facto "go-to" sledding hill after after every snow fall. Their parking lot can fill with literally 100 cars with many more walkers arriving.
Does the club have any liability for negligence if a child gets injured due to unsafe conditions? Perhaps too many people sledding at a time to be safe or icy walk-ways on the way to the top of the hill?
Again, I am not sure if the sledders are considered trespassers or are even technically welcome. After decades, it is inconceivable to think the club doesn't know the popularity of the hill and has done nothing to dissuade its use.
You are lucky that your golf couse still allows the off-season use for sledding and other traditional winter uses. I can't give a definitive answer to this, except to say that our local hilly country club revoked permission several years back for sledding because of some accidents (sleds crashing into one another willy-nilly from different hills) and the probable advice of their insurance carrier that if they knew of this activity, which they surely did from the cars parked along the highway all winter, although it might be considered trespass, their knowledge and implied permission might elevate the rights of users to the level of "invitees" to which some duties were allowed, such as to regulate areas of sledding, provide staff to assist, etc., or be considered an "attractive nuisance" like a swimming pool or dangerous waterfalls without "keep out" signs or fencing.
Of course, in our legal system, anyone can sue a property owner for negligence and hope for at least a nuisance settlement to avoid litigation and a trial, and then insurance carriers tend to increase their premiums, so, sadly, sledding and skiing permission was revoked and there is no sledding at the Country Club anymore, as there had been for many decades.
Although intitially there was a publicity hit in the local papers and some pushback between the perceived rich country club toffs and middle class families, most people blamed it on "the lawyers" and the Country Club was not shamed into reconsidering its position, so the ban continues to this day (fortunately, our City has some parks with sledding hills, though they aren't as numerous and steep as the Country Club's!)
An attractive nuisance is something that may attract children to your property and be dangerous to them, like a pool. You may be liable for injuries it causes.