Two friends of mine (who were both experienced walkers with Mountain Leadership Certificates) walked it 'bit by bit'. (i.e. they'd cover part of the route during one holiday, and then return later in the year to do the next bit). One evening they descended to their B&B and, after a good night's sleep set out really early again on the following morning. It was only after more than two hours walking that one of those two experienced hill walkers (with excellent map-reading skills) realised that the sun appeared to have risen from the west. Yes, they'd been walking back the way they'd come from!
You might find this detailed diary useful:
http://www.gtleisure....ks/pw07/penway07a.htm
Chris