Speaking of flat rides; I was this very morning taken to riding somewhere steady and flat. From here it's little lumpy getting there and as a consequence it's lumpy getting back.
As per
@ColinJ 's 'Garforth Ride' comments in the thread the roads east of Leeds are pretty flat. The main road out to Selby is super flat and apart from a couple of bridges there is noting to climb. It's a little busy though (or seemed to be this morning at least).
Ot the return I came via the very quiet road through Gateforth and a 3 mile stretch between there and Monk Fryston varies by only 30ft or so. I particularly enjoyed that part of the ride. Warm sun, a flat pleasant smooth road, grassy verges and fields of crops growing apace in the warm weather. All that and nary a hint of any car, motrobike or truck.