As of now, a Discover Pass is required to park at the entrance.
This is a part of the extensive Tiger Mountain Trail network. It's been around for a couple decades, but has gotten some new attention within the last few years.
The Preston Railroad Trail descends gradually at first before steepening and leading you through a series of long switchbacks. The trail starts at the fire road that accesses the Tiger Mountain Summit and terminates at another fire road to the northwest of Tiger Mountain.
Along the way, you'll be running through dense forest and will cross some ephemeral streams.