Riding Really Good Mountain Bike Trails

I had forgotten how riding really good, technical mountain bike trails can give you one hell of a workout. The Lykens Rattling Creek Trails are such beasts -- a couple times on Rock's Ridge and the old quads are squealing. I'm growing bored with the same trails at Rattling Creek, but they definitely give you a workout. Lately, I've sorta been takin' it easy on the bike -- a road ride here and there, a trainer session, or an easy ride on the easy stuff on the RCST trails. Last night I finally got a decent, technical, 2+ hour mountain ride in and it felt SOOOO good. I hurt today! And it's a good hurt. It made me realize I gotta get out more on mountain trails. I live about a mile from the side of a mountain that has an old, washed out jeep trail going to the top that the four-wheelers ride all the time. The first part is an 8-10 minute, rocky, "tech-fest" climb that is an awesome workout. Once I get up the rideable climb, I can continue another 15 minutes to an old mining trail -- but that has to be walked because it gets super-steep and rocky. Then I can ride the mining trail along the ridge of the mountain. I don't hit it too often 'cause the abandoned open mining shafts give me the heebie-jeebies, but its an awesome, close-to-home rocky, technical workout. Of course it's not near as good as living in the center of Michaux... but it'll do!