Ian H
Ancient randonneur
Apparently the route is very well marked out.
Check out the PBP thread on the YACF forum for more information.
There are 15 gps tracks/routes to download from Openrunner via the PBP website here.
However the route is clearly marked at every junction. The only danger is from people removing signs. This can happen late on and towards the end as some folk grab souvenirs.