Dickson and I are running the CCT-RCP Loop (21 miles) on Sunday morning at 8:30am. Starting at Barnes & Noble in Bethesda, then head down the CCT, cross over to the C&O Towpath, run past the Gtown Store, left on Rock Creek Parkway, back up to The Line and then take the Georgetown Branch Trail back to Barnes & Noble.
SEE ROUGH MAP HERE - this can be adjusted/amended to go more/less.
If you want to run 20+ this is a good one. If you want to join in for part of the fun, you might be able to jump on our train at a few different places (ie - the Store which is roughly mile 7)
I'm running the usual 10 from the Store on Saturday at 9am.