Sure. It's off of Route 38. If you're in Redlands, head east on Lugonia and into San Bernadino National Forest. After you enter the park, there's a trail about two miles in on the left. It's pretty easy once you get there and the trail is marked.
Google maps calls it Warm Springs Truck Road. Follow that to Thomas Hunting Ground Trail. That trail turns into the Santa Ana River Trail which runs right back into Rte38. Turn right and you'll drive out of the forest and back towards Redlands.
Let me know if you want more info!