A long spoke that starts with NCN12 to N Mymms 6.2, where Spoke 11NE crosses, X-wing style, so you can jump ship and proceed NE towards Hatfield.
After the climb to Dancers Hill Road, R on Dancers Lane 2.3 (scene of the worst example of fly-tipping I witnessed), a grim passage under the M25, and then off-road beside the old A1 for some miles - much quieter and pleasanter than you might fear.
Leaving NCN12 and crossing A1(M), the road to Colney Heath 7.6 is busy by Cycle Orbital standards. Cross A414 8.3 by ramped footbridge, or (now, 4/21) traffic signals) and at 9.5 Arc 12 inner on Alban Way for St. Albans and Verulamium.
The spoke continues, passing through Oaklands College 9.7 - 10.6 where it is joined by Spin-off 12 for the duration, then up House Lane to Sundridge 12.2. Another busy road here, the B651, so a small detour R at 12.5 keeps the ride rural.
Turn L 13.1 to regain B651 13.6 – and a choice: 1] straight for Normansland Common and after a fine ride through Amwell and a steep descent on Leasey Bridge Lane 15.3 - brakes on for sharp L on Arc 12 outer to Harpenden. This is the gps tracked route, being true to the NW trend of the spoke.
But back to B651 13.6 – 2] R, then 200m bear R signed for Devil’s Dyke – in fact part of the defences of the Belgic Catuvellauni Oppidum – to join, west of Wheathampstead, first Spin-off 12 for Stevenage then Arc 12 outer for Welwyn.