This is the map GISRUK 2010 attendees are using to get from UCL, where the conference is, to the River Thames, where the boat await for the evening cruise. On the way, some of them are doing the challenge, which is to take the optimum route to visit any 6 of the 12 control points – a blue plaque at each one to prove their visit. The map was made using the OpenOrienteeringMap map builder.
(Note: The start point was actually from just east of “B” rather than the triangle.)
I haven’t yet computed the best route, I think it’s probably BAJFED or maybe BMCKED. There is no “trick” best route, as the points were fairly fixed by the locations of the blue plaques. But the solution is apparently not immediately obvious to the human eye.