Small world - I recently started a new job in Biggin Hill, and a section of your driving route there is actually now part of my new commute! Waypoints 4 - 6, after I come off the M25 J4. Google/Waze always tries to take me further along the A21 and then down one of the backroads, but although its the shortest route, it's also quite narrow and annoying to travel down at school run time. I found that adding a mile or so to got though Knockholt was less busy and it was quite a pleasant little driving road as well Unfortunately, it's closed all this week, so I have to go the other way again :/I really like that road, even though it can be quite narrow at some points. I normally do this route https://referal.roadstr.io/c0RL/agismxu8
If you ever want to do a early Sunday blast at some point let me know
Oh, and just a tip - I'd avoid the A225 from Eynsford down to Otford for a couple of weeks; that's the way I came yesterday morning, but they have just surface dressed the whole section from S-bend under the railway bridge (just after Castle Farm) down to Shoreham Station. I had to crawl along at 20mph. Had a pickup truck come blasting up behind me, I pulled over and luckily he went very wide so I didn't get blasted by gravel. They're doing a lot of surface dressing all over at the moment so I'm trying to keep a mental map of roads to avoid.
Might sign up for Roadstr, seen a few Youtubers mention it.