Too chilly for me to be outdoors for 16hrs i'm afraid. Good luck to the Audacious randonneurs who give it a go.
Any reason that the finishes along the A40 nowadays? I know Oxford Station rail bridge is closed to motor traffic but assumed it was open to peds. Or is it to do with minimum distances?
I think because the control put in at Bampton to ensure minimum distance is 300km makes this the shorter route, it's about 7km further and having to contend with oxford city centre traffic.
Eynsham - Botley - pear tree = 15km
Eynsham - A40 - Pear tree = 7.8km (4.8km on the A40)
However personally I would rather cross the A40 at Eynsham, and proceed through cassington and yarnton to return along the A44. It's only the same length of A44 used on the outbound route, and there is a wide pavement that may or may not be officially a cycle path, but looks very bike suitable if traffic levels make people uncomfortable.
Eynsham - A44 - pear tree = 8.1km (1.6km on the A44)
I don't know if the organiser has decided the A44 is not bike suitable in the evenings, or if this is done to avoid confusion on the outbound route with the fork in the gpx track.
if I had used the A40, I certainly would not loop all the way around the A44/A34 junction to enter the services as per the route sheet, instead taking the park and ride exit and walking in to the services from the pedestrian stairs in the corner of the services car park. (maybe lock the bike in the car before getting a receipt)