I did the Sustrans route from York-Hull a few years ago (it goes via Selby) - not sure I'd recommend it, though, as I was on a hybrid and found some sections a bit rough. Definitely wouldn't do it on a road bike.
There's always the latter part of the York-Hull FNRttC route, which goes via Goole and Flixborough - though having ridden some of the parts round Swinefleet and Ousefleet in daylight, I found them incredibly dull. I didn't ever think there could be such a thing as too flat until I rode that bit!