If anybody is interested, I am part of a saturday morning running group (averages 4 to 6 people) that does a 9-mile trail loop starting at 6:45 am. We meet at the RCP trailhead off of West Beach Drive, close to the DC-MD line (I believe the trailhead is at the corner of W Beach and Plymouth St NW or W Beach and Parkside Dr NW...they are about a block apart and the exact street escapes me right now). The loop is all trail with some pretty good hill work spread throughout. Pace for the lead runners is about 7:30/mile, but there are folks in the group who run closer to 8:00/mile. It's a friendly group with a mixture of experienced ultradistance runners and triathletes...as well as a couple of new marathoners who just joined recently. 3 of us live in Woodside Park near Downtown Silver Spring, so we tack on another 1.5 miles to get down to the trailhead and then 1.5 coming back, both run at a pretty leisurely warm up/cool down pace.
We occassionally ditch the regular loop for a long hill workout/time trial (about 17 miles RT) and repeats on Holly Hill, when we are in the mood for some punishment.
If you're interested, shoot me a line (email@example.com) and I will add you to our email group.