Routegadget is a great tool for post race analysis of your route choices. You can also see the routes taken by others.
Adding your route is quite easy. You can draw your route manually or upload your GPS track either as a GPX or TCX file.
User guide for Routegadget 2 here.
Please note that in line with FRA rules you cannot use a GPS watch to assist navigation during the Peak Raid3 events. However, wearing a watch for tracking and post-race analysis is allowed.