The hardest areas to find the best route for the C25 circumnavigation were both in Surrey; Chipstead to Epsom and Woking to Windsor, or the lands of Horse and Golf respectively. This latter is peppered not just with golf courses but also private estates, busy roads and byways over heathland where your wheels can sink into either soft sand or bog. There is an acceptable Woking to Sunningdale road but it is 60mph, and Chobham is quite a bottleneck. Take it if you are in a hurry, but you will miss out on a quirky, entertaining ride.
This – the Chobham bypass – took a while to find, but it is a delightful adventure, detouring at first to the west via Penny Pot and Sparrow Row in a series of short lanes and involving not one but two ford crossings of small streams, and then east, after crossing the M3, over Chobham Heath on an acceptably surfaced byway (as shown). Here is a more bosky, peaceful and welcoming Surrey. It is possible to cycle past barriers and no entry signs and on through Wentworth golf course and estate, but I think you will feel more at ease on this route.