Not sure this will help, but in case ... it's a while since I lived in that neck of the woods- some things change; some don't ...
Could consider the 724 bus from Uxbridge to Watford Junction, then pick up a train from there to Tring.
Bear in mind that Tring station is not really in Tring at all, it's almost two miles away.
A good option. Bear in mind the 724 is broadly hourly and can get caught up in traffic en route Heathrow to Harlow via Uxbridge and Watford Junction (
https://www.intalink.org.uk/services/ec0597df-e2ad-429e-a5cb-047edabd9c4e) Trains Watford Junction- Tring are good and regular. You can look up 724 and train times online, and bus stop locations on Streetview.
Option 2- a different bus. 140 from Hayes&Harlington stn to Harrow&Weadstone stn, via Harrow town centre (and Harrow-on-the-Hill Metropolitan line stn), about 50mins(!); approx every 10 mins. There's a TfL Superloop bus too (limited stop) from H&H to Harrow town centre, but that's then another bus (or long step) to H&W stn.
There could be options via Rayners Lane but they may be more circuitous and less frequent ... maybe someone else may be more knowledgeable on this.
In short, to use that wiseguy way with words:I wouldn't start from here

... or aim to get there!
ps You may enjoy some views of HS2 works en route on the 724!