Well, if it is cycling history you seek, may I suggest my own country. Italy. IMHO, the other two countries worth visiting for cycling history are Belgium (you too can cycle all the muurs!) and the contiguous area in France, for the Paris-Roubaix cobbles.
And it is Madonna del Ghisallo, patron saint of cyclists, and cycling museum, with Coppi, Bartali and Merck's original bikes, to name a few.
Read all about it:
www-math.science.unitn.itMadonna Ghisallo.htmlOpen ↗
Beautiful area for general tourism and riding, as long as you stay away during the weekends, when three quarters of Milano invade the area!
For general tourism information check out: larioonline.itlarioonline.itOpen ↗ they have an English section also.
And of course, you should also make your way up the Croce d' Aune and pay homage to Tullio Campagnolo!
There is a well known race there with a good web page with all the info you need, also in English: http://www.pedavenacrocedaune.org/