Just off Fryman Canyon Rd. is Wilacre Park (according to the Thomas Bros. Guide, P. 532/G-7 & P. 592/H-1), otherwise known as Fryman Canyon Trail in the Santa Monica Mountains (a.k.a. 'the hill') National Recreation Area. There are many trail systems along boths sides of the hill, but this one is my favorite because it connects Laurel Canyon to Mullholand Dr. Fryman Canyon Scenic Overlook.
Park at the foot of the hill at Fryman Rd. The walk starts off as a paved fire road of steep switchbacks which level out at a clearing where you have three choices: go back down via a steep and narrow downhill trail through the field, go straight and to the left along the trickier narrow trail which parallels the fire road (my pick!), or keep on the switchbacking dirt fire road.
The side trail and the fire road meet up just before a watering hole of sorts at Coldwater Canyon Park (a wood chipped area where there is a people fountain and a doggie fountain). Here you can take a right to Coldwater Canyon Rd. straight and up a railed trail (these two have been unexplored by me at this time) or continue down the fire road downhill until you hit the cul de sac of Iredell Ln. (my pick).
Three choices here: 1) turn around and retrace. 2) go down Iredell Ln, left onto Fryman Rd and return to parking lot, making a nice approx 2 mi loop. 3) take the trail just after the first house on the right, past the cute fenced in dobermans (my pick).
Choice 3 goes steep uphill and should really only be attempted with ankle supporting boots unless you are an experienced hiker or trail runner. I saw a girl break her ankle while falling down a ravine in tennis shoes. This trail is steep upgoing, so use the rail road ties like steps. Follow the main trail; I have yet to discover the offshutes, but think they lead to dead ends and private property. The trail hits a few downhill switchbacks into an area called the Rainforest, a lovely ravine filled with Eucalypts with a little stream running through. This trail runs .9 miles to the Deering Tr. (sign will point you on your way) which runs up and down more narrow switchbacks 1 mi to a stream and what I call the car graveyard; remains of cars buried in the hill and brightly tagged by kids. This trail runs another 10 - 15 min. Hike up to the Fryman Cyn. Overlook which allows you to spy the entire valley, smog and all. On a clear day you can see Ventura County.
I have not found any organizations giving out trail maps. Best way to do these trails is just to have fun and explore! Who knew you could do this in the Valley?