We will be driving from Keswick to York on 01 Sep and have a full day to see the Yorkshire Dales enroute. Any suggestions on what towns/sights to see on the way?

Well, not really, but looking for the same suggestions for a day or two in June, so I will follow the answers you get.

In and around the Dales

Hawes - home of Wensleydale
Skipton - gateway to the Dales
Ilkley - and it's moor Baht 'at
Malham - for it's cove & tarn
Kettlewell - setting for Calendar Girls
Bolton Abbey & The Strid
Ribblehead Viaduct on the Settle-Carlisle Line
Pateley Bridge - nice little village
Parcevall Hall Gardens - nice contrast between moors and garden
Bingley - canal lock system dating to before the founding of the USA
Haworth - needs no introduction
Worth Valley Railway - as seen in the original Railway Children
Harrogate - reet posh (but not as posh as Ilkley)
There are also several limestone cave systems

We spent 10 days in that area recently. Stayed at Harrogate. Visited Bolton Abbey, Pateley Bridge, Grassington, Aysgarth, Richmond, Ripley, Ripon, York, Knaresborough and Fountains Abbey. What a beautiful area. Definitely plan to return, perhaps in 2016 when the Minster's East Wing stained glass windows are reinstalled. The locals are delightful.

I'm grateful to Morgana for her excellent advice. That #36 bus was a lifesaver.

Happy to advise a route and things to see - can you let me know your interests, if you want to do a walk, stop for lunch etc, and I'll do my best to sort you out a great day!