Arlington 4 empty tour bus 7 meet near doubletree 9 10 11 escorting ups trucks 43 44 45 47 48 135 post; bus 42 213 enc USMC 63033 water point 63037 aid station 63039 63040 bring back commandant 63045 pickup point 63046 "start" coordinate time pieces 63047 searching bags 166.725 169.775 462.7 97.4 DC 2096