Pleasant town as a cycling hub?

We rented in Bruges and rode the canals. And the same in Haarlem with bike paths everywhere to the coast and to Amsterdam. I would prefer Haarlem as a town to center in.

You'll like Zutphen, in the eastern part of the country, 1,5 to 2 hours by train from Amsterdam.
A gem of a small historical city, within easy reach of totally different landscapes: the river IJssel with cities like Doesburg (to the south) and Deventer (north), the inland area with castles in Vorden and Ruurlo, or across the river to the wooded Veluwe.
There are several bicycle rentals, whose websites, I'm afraid, are Dutch only. You could however contact the local tourist information.

Leiden is a nice university town with great bike riding possibilities. There are paved paths through the sand dunes to the sea. It is a realitively quick train ride to Amsterdam too.

Thank you all for your responses! Zutphen sounds like it has everything we could want, but it also sounds as though we can't go wrong given the cycling culture of the Netherlands.

We spent four nights in Zutphen and loved it! We rented bikes (there's only one shop we found that rents, and they were great to work with) and took two day trips in different directions to neighboring towns with windmills, castles, woods, rivers, wildflowers, and pastures along the way. It was very scenic and easy riding. Zutphen has a great Saturday market, a lovely town square with delightful cafes, a 16th century chain library, and a lovely old cathedral. The other tourists we encountered--and there weren't many--were from the Netherlands. Our B&B host said in the last 15 years she'd only had three guests from the U.S., so we felt like we truly experienced life in the Netherlands. Thanks for the recommendations!

Good to hear you liked it. It is a lovely part of the country, and Zutphen is a real gem.

Good to learn that an off the beaten path experience really pays off.