Milan is a big city.
Venice is a pedestrian, tourist cesspool.
The areas surround florence (tuscany) is nice and idyllic...and youre not off from siena which is one of the gems of the country
Not sure if youre after a sight-seeing vacation with riding mixed in. Or a riding-vacation...in which case, head for the alp countryside be it in switzerland france italy or austria.
Of course, one of THE global cycling destination is spain. Mallorca being a specific example