Pretty sure that’s possible as a day trip by train. Direct Kings Cross to Leeds train, just need to get to London first.
I do (or did, last time was about 6 months ago) day trips from West Berks to Leeds by train. Easily doable and if you were to drive to somewhere like SOU Airport Parkway and get a fast to Waterloo the overall times would be about the same as mine from the Newbury area into Paddington. KingsX to Leeds is about 2hrs 15min and runs (or did) every 30 mins.