See larger version of course map.

0.0    Begin at Iwo Jima
        Go through Rosslyn
        Cross Key Bridge

1.0    Sharp right after bridge thru Key Park down to river side of C&O Canal
        Left on C&O Towpath and QUICK right down steps to Water St.
        Right on Water St. to trailhead of Capital Crescent Trail
        Continue on Capital Crescent to mile marker #6.5 (see note below about shortening route)

5.0  Just past MM #6.5 U-turn at water fountain
       Left onto trail about 100 yds after DC border and about 1/4 mile from U-turn
       Follow trail (with chain link fence on left) to Potomac Avenue
       Follow Potomac Avenue (Enjoy the nice homes and scenic views of the river)

6.0  Turn left onto Galena Place. Run a little more than 2.5 blocks.
       Turn right on unmarked trail just before Sherier Place
       (The trail is an abandoned railbed for streetcars from Georgetown to Glen Echo Park!)
       (If you miss trail, continue to MacArthur, make a right and follow to left on Chain Bridge Rd)
       Continue on trail across pedestrian bridge over Arizona Ave.
       Continue on trail through parking lot at Palisades Rec Center
       Turn left onto (paved) Chain Bridge Road (#2402 will be on your left)
       Cross MacArthur Blvd

6.75  (Begin Loops of Battery Kemble)
       Continue UP Chain Bridge Rd. Enjoy the hill--You will see it again ;-)
       Right onto gravel road toward parking area
       Right onto trail at bottom of the hill
       Continue on main trail that follows creek (on your left) through B.K. park
       Exit woods at MacArthur Blvd.
       Right along MacArthur for about 50 yards
       Right onto Chain Bridge Road.

8.0   End of first loop. Repeat loop (see note below about shortening route)

9.25  End of second loop
        Return by retracing your steps (see note below about shortening route)
       Downhill on Chain Bridge Rd to #2402
       Right onto unmarked trail (old railway line)
       Run through parking lot at Palisades Rec Center
       Cross pedestrian bridge over Arizona Ave.
       Left onto Galena Place
       Right onto Potomac Ave
       Straight onto trail that connects to Capital Crescent
       Right onto Capital Crescent (see note below about shortening route)

11.0 U-Turn at Water Fountain at Capital Crescent MM #6.5
        Follow Capital Crescent to Georgetown
       Cross Key Bridge
       Through Rosslyn to Iwo Jima

16.0  Finish

Notes:

To shorten route: Do not run all the way to MM #6.5 Instead turn right onto trail about ¼ mile after MM #7 and follow directions from Potomac Avenue

All distances are approximate.  Your mileage may vary.