A Fly-Over (termed "Tour" in Google Earth) is a natural "addon" after spending the time to accurately design and plot out a particular Trip. It can be viewed by others in Google Earth but of course is far more accessible as a Video within an App.
The result of rendering a Tour as a Video has been vastly improved in Google Earth Pro by virtue of MS Movie Maker being embedded as a tool, thus avoiding the use of "screen recorders" with their various shortcomings, so that is the method we now use.
These Fly-Overs are recorded so as to speed up the trip to about 150 MPH. The Fly-Overs follow the routes plotted out in Google Earth as described above with odd numbered legs in Orange and even in Red. As such they closely follow both the Walking and Vehicular Sat Nav routes. As a comparison the total distances are:
1. Ogilby Map = 156.5 miles (and introducing the Statute Mile)
2. Fly-Over = 163.8 miles (158.8 without Pembrokeshire diversion)
3. Sat Nav Walk = 162.5 miles
4. Sat Nav Car = 167.3 miles
You can play the Fly-Overs for each of the 12 Sections in the Southbound direction by selecting the icons at the upper left in Frame 3 or the Northbound (return) journey via the icons at the lower right.