Hello everyone! I'm the de facto race co-director for the event, so hopefully I can answer (or elevate) some of your questions. We all expec to know more information in a few days so please bear with.
The bottommost portion of the course will be slightly different and unfortunately it features more asphalt; the Golden Gate Park & Rec has closed off parts of the sandy portion of the single-track adjacent to Chain of Lakes Rd. which feeds south off of JFK Rd. Instead of the sandy pitch, there will now be a ~200-meter stretch on an asphalt bike path that will feed back to the climb back up to the Polo Fields.
A second issue brought to my attention is the 3/4-mile Polo Field. This part of the course was an old horse track and is an integral part of the race. Apparently its surface has been observed to have been rendered somewhat harder than usual in the past week or two by some guys who train out there with some regularity. It was either the recent rain washing away a dirt surface, or someone speculated that the park may have laid down some gravel on top to firm it up for vehicles that may be performing some park maintenance.
There are three meadows of varying quality: Speedway (bottom/lumpier), Lindley (middle-also lumpy but less so) and Hellman (topmost portion a little smoother). These meadows hold water well if it rains, but if we get heavy rains then you'll find yourself running on a very slick surface. The other portion that is tricky is the trail that parallels JFK Drive. It is fraught with some cobbles as Cush has mentioned so between that and the lumpy grass, your proprioception comes into play.
We're running the PA and Western Region USATF Champs on Sunday, so I'll know more about the course then. We also have a meeting on the 17th so if you have any pressing questions please post them here and I can bring them up at the meeting.
Unfortunately, I would consider bringing multiple shoe options: soft cleated shoes like Inov8 195s have been known to work, straight up XC spikes especially if it's wet - but of course they are a rough ride on the asphalt portions, or run the risk rolling the ankles in Flys or some variation of snap-plate shoes. (Some people will go for it and run in those).
Cheers and looking forward to seeing you there.