If you are considering walking this route yourself, please see my disclaimer. You may also like to see these notes about the maps and GPX files.
On the far side of the field, I turned right behind the hedgerow and followed a bridleway along the edge of another field to reach Great Widmoor Wood. The bridleway continued on through the wood, and in about a third of a mile brought me to a road, where I turned right (virtually straight on) to head to Kingsash.
The bridleway after I turned right, heading to Great Widmoor Wood
Great Widmoor Wood
Great Widmoor Wood
The road into Kingash
The road continuing through Kingash
At a lane junction in Kingsash, I intended taking a footpath starting just a few yards down the lane coming in on the left. But there was a foootpath diversion here because of some work being done for the HS2 railway (I believe it actually runs through a tunnel here, so I suppose the work is to do with ventilation shafts and acces roads and such like). So I followed the diversion sign by continuing down that lane (named King's Lane on the OS map) - I was a little annoyed, but at least I would be walking some paths I'd not used before. I could see that the HS2 work was quite extensive, so I correctly guessed that the next path on the right would also be diverted (I've walked it at least twice as it's part of the Chiltern Way). The next path on that side (at Strawberry Hill Farm) was also diverted, so I followed the lane for about three quarters of a mile in total, to where the next path went right immediately after Bowood Lane came in on that side (that lane was closed off here, but there was a 'Path open' sign at the start of the footpath).
Footpath diversion sign
The diversion along King's Lane
The diversion along King's Lane
View right from King's Lane (I've carefully managed to avoid most of the scars caused by HS2)
The diversion along King's Lane
The diversion along King's Lane
The diversion after I turned right immediately after a lane junction
The path ran through a small wood with the lane just to my right (it must have been closed for sometime, it was in quite a state). On leaving the wood I reached part of the HS2 construction works. I soon came to a gate where a sign said pedestrians had to wait to be escorted across the site. A security guard came out of a hut here, and talked to someone on his walkie-talkie to stop vehicles moving across the line of the footpath. I was then allowed to walk across to the other side (there was a gate, hut and secuity guard on this side too). The path then ran between tall green security fences either side for two or three hundred yards (it felt like I was in a long thin cage) until the fence ended and I could continue down Bowood Lane (the footpath should still have run to the left of the lane, but that was still inaccessible). I soon spotted a nice patch of Rosebay Willowherb growing next to the lane.
Where the path reaches the HS2 construction site
The path after I was escorted across the HS2 construction site
Bowood Lane