The Surrey Downs are Cycle Orbital’s biggest challenge, and the east section the most dissected; the GPS reports 280m ascent and 370m descent in 16miles. Clockwise however you start at the top; Botley Hill 267m is the circuit’s highest point. Woldingham Road is quite busy, but its continuation Gangers Hill 1.7 quieter. It is steep and narrow in places however, culminating - CAUTION - in 2.9 a sharp and steep L bend immediately before VERY SHARP RIGHT onto private track for Woldingham School.
At Winders Hill 3.4 Spoke 3 and NCN 21 join. After a short off-road section, bizarrely, being in such deep countryside, past a factory depot 3.7! Take steps R and short bridleway to avoid an unrewarding loop; 4 head L for bridge over the A22. On the steep climb that follows, L on a bridleway that emerges with the North Downs Way at the fine viewpoint on Gravelly Hill 4.7. (You can stay on the steeply climbing road, Tupwood Lane, if you wish). At Gravelly Hill there is access R from Caterham, then Spinoff 6 NCN21 dives L 4.8 down for Redhill Gatwick and Brighton.
Cycle Orbital clings to the scarp edge (now the Pilgrim’s Way too), and at 5.9 White Hill Lane (L for Spinoff 6 NCN20, shortly to merge with NCN21 at the M23/M25 junction below) it’s an off-road section to 7.5 Tollsworth Manor Farm. 7.8 join B2031 briefly; signal R for straight on at bend 8.2. Dean Lane leads down to the 9.1 A23 trunk road; turn R on slip road, and mercifully a controlled crossing awaits. The road up to Chipstead Church 9.6 is one-way at 9.3; until cycle-only contraflow is adopted, rather than detour R on Church Lane Ave and Star Lane you might take the hill at a walk.
Now on Hogscross Lane and High Road you have earned three miles of open road gentle ascent (turn R Babylon Lane 11.8) to A217 busy trunk road 12.5. Either walk across the dual carriageway in two stages or use the roundabout for Stubbs Lane. At Mogador 13.4 you are off-road on bridleway through Corporation of London heathland and woods, until the landscape opens out crossing a golf course 14.1. The B2032 is another busy road to cross 14.6, thereafter a quiet run into Walton-on-the-Hill, which has all facilities for a stop (including a bike shop).