As I'm hoping to do the KAW in 2022 I got a copy of the CTC
1 guide book. It's not possible to definitively say what the route is as there are alternatives for many sections of it
2 and none of it is waymarked on the ground. Since you can't say what is 'the route' nor can you say what isn't.
However... (you knew that was coming)
The c.t route I linked, for example, takes the main route through Amesbury, presumably to take in a cafe there of global significance rather than passing a bunch of rocks just west despite the latter being a poster child for the route. It is also off both main and alternate route in places. Not significantly, but off.
Anyway, here's another gpx that is my making:
https://cycle.travel/map/journey/278551That follows the KAW as shown in the book using the alternates sometimes and others not. If such things get under your skin then maybe this is a better gpx to download. But do it soon, I'll be bollocking around with it to get 3 agreeable overnights reasonably distributed so it won't stay 'right', if I dare claim that, for long. Easiest way is to register for c.t, delete my overnight halts (to make a change) and then save it as your own route.
Really though, you could follow the guide on cycle.travel and you've done it. Anyone who claims otherwise coz you missed a rock, mound or muddy field is talking arse.
1Yeah, I know.
2Some for weather/mud reasons, others for time rich sight seeing / time poor gotta press on reasons.