The K and A lends itself to railway linked walks. Train to Trowbridge, walk to Devizes, bus to Bath.
Train to Pewsey, walk to Devizes and bus to Bath.
Pewsey to Bedwyn is another
Nice level walking with plenty to see.
Unfortunately I didn't spot this thread before someone else came up with the right answer, so I'll go off on a tangent and respond to this instead
I have cycled the complete length of the K&A towpath from Bath to Reading, and walked a fair bit of it as well. Going east it is reasonably well-surfaced from Widcombe locks at Bath to the eastern outskirts of Devizes (although even on that section there is a dodgy length around Seend). From Theale into Reading it is also reasonably well surfaced, although part of the "towpath" is nowhere near the canal as it passes by the M4 Reading Services. There is a bit of private land there that causes the diversion.
Between Devizes and Theale it is generally only surfaced at the locks and wharves, and the rest of it is grass. Or mud... You can have excellent walks along it as long as there has not been any substantial rain lately, which tends to preclude the winter months because it won't dry out much even if it hasn't rained for a week.
One particularly lousy section is between Froxfield and Hungerford, where it essentially runs along the edge of a field. This field usually contains cattle and, when they want a drink, you can guess where they go to get the water from. Heavy buggers, cows...
There is also a tunnel at Burbage and the towpath leaves the canal for a bit and starts again on the other side.
In case anyone is interested, here s the the view that Streetview gives of that bit of railway at Avoncliff:
https://www.google.co.uk/maps/@51.3391305,-2.283005,3a,53.4y,244.92h,86.44t/data=!3m6!1e1!3m4!1s3RFZGUu3H-tFey_KUmYMuw!2e0!7i13312!8i6656
