I did this in 2012, on a touring bike. Trans-Pennine Trail from York to Hull, overnight ferry, then cycle routes up the coast to Leiden (not far from Amsterdam). I’d recommend it, if you don’t mind flat.
The route through Yorkshire is fine, but too bumpy in places for a skinny road bike. I have yet to find out how to pedal through Hull from the Humber Bridge to the docks; signs disappear, the TPT forgets where it’s going, and there always seem to be roadworks. Drinking heavily on a boat, having earned the right to do so, is always good.
Once in Holland, it’s easy but slow – there are so many bike paths I kept getting lost. A map would have helped, but I wasn’t in a hurry. The ferry stops miles outside Rotterdam, but you can avoid the detour through the city by taking a ferry North across the river at Maasluis (pronounced “mass-louse”) a few km inland from the ferry terminal. Taking the cycle path along the coast (once I found it) was very pretty.
I arrived on National Paint Yourself Orange And Sell Off All Your Broken Tat On The Streets Day (Queen’s Day?), which made it really hard to get through the towns, but good beery fun nevertheless.