Sorry, it’s not a real answer to your question, but I would really recommend a Sat Nav of some kind.
When I first started riding, I really enjoyed the feeling of ‘no last bus’ freedom that it gave me, but quickly found I was often sticking to bus routes and often getting lost.
Since starting to use the TomTom I have, that sense of freedom has returned as I know I can go anywhere and I will be lead home.
Sure, they might not be correct 100% of the time, nor lead you along your preferred route, but I can at least rely on it. When following people to Blackheath last Friday, I got left behind (of course!), sut wasn’t stressed, as I was able to get there and back easily.
I know the central Ldn>>>H’smith part of that journey. It’s always busy, whichever way you go. The way suggested above is as good as any (Embankment is good and wide - so you’re fine filtering there. I haven’t been down Ful Pal Rd for ages).
The simplest way is to go to Central London and then follow the A4 signs (Picadilly>Harrods>V&A Museum>Hammersmith). It’s easy, and there isn’t any significant navigating to do, but it will be busy at that time of night.
Otherwise, you can go Embankment>Earls Court>A4>H’smith, which, again, involves next to no navigating.
If it helps, Borough to Chiswick R’bout would take me about 30 mins at that time of day