Well; an intresting question! I've just completed ascending all the Yorkshire Dales NP 2000ft Hills (not in one go, though someone recently has). I thought I had done them years ago, but then heard about the recent elevation of Calf Fell above Barbon to the number. Had a lovely day out a couple of weeks ago climbing this and was impressed by the decorated Trig point -as well as by the view, lack of people and wildlife.
It's a long way between some of them and would probably involve a fair bit of road running.