Thanks Jon. I rode it years ago, probably 2010, so can't remember how steep the hill is. Hopefully I'll have a geared bike in time but will singlespeed if there's a glitch.
I think they switched it in the past few years from the west side of the park (where they hold big dog mtb race) to the east, where the gradients are a bit gentler.
I rode it geared last year. I'll be on a single speed this year running 36x17 (~55").
The hill isn't all that steep so it shouldn't be much of a problem. Might spin out on the grassy descent if it isn't broken up with corners though.