Yes, it would be easier if we could use some parts of the current circuit. It sits square in the middle of the Principality, so I found I was forced to go either east or west of it, which really limited my ability to do anything.
I’m just going to jump in here and submit this, an entry that does use parts of the circuit, just in case Kingshark changes his mind:
http://www.gmap-pedometer.com/?r=5818915