Wilderness Park is only open to Swamp organized Night rides. Everyone has to checkin together and out. Even if you park elsewhere and ride in, you still aren't supposed to enter the park at night without special arrangements.
In fact the only Swamp maintained trail that is always open to night riding is Croom. The parking lot at Alafia also closes at dark, but you can ride at night if you camp -- I suppose no one checks to make sure you don't vacate your campsite before dawn if you want to pay $22 for a site. Balm has two organized Swamp night rides per month, check the Swamp schedule to be sure, but basically it is the 3rd Friday of the month and the Friday closest to the full moon. http://www.swampclub.org/calendar.htm
I've done the Balm night ride a few times, and it is great. Just wish it was mid-week instead of on Friday.