---Can anyone recommend any "must see" cycling related attractions that merit a visit in the vicinity?---
Siena is absolutely not to be missed as a cultural destination -- I enjoy it more than Florence. Oops, but I'm not addressing the issue of cycling destinations. There's a nice little shop in Siena, Centro Bici, with a team jersey that features the tower at the Siena Campo -- I usually pick up a couple as gifts. As a matter of fact, if you could pick one up for me, assuming they have a size 5, which they never do, I'd be thrilled to pay for it. Non parlano molto Inglese (but cash is the international language).
In Florence, the Bianchi shop has a great "David" jersey. Florence is one of the best town bike cities in Italy. You'll see lots of cool, and old, townies, being ridden by immaculately groomed and suit-clad fiorentini. Check out the bike racks for well-used old gems. Padua is maybe the #2 town-bike town, and also the home of Alan, but I digress.
Lastly, in downtown Florence, just off the main drag, there is a photographic studio, Foto Locchi. They have an amazing archive of classic cycling photos, and they will make prints for you. I bought a bunch of Coppi and Bartali pix from them.
Side note - if you need a couple of restorative beach days at the end of the trip, it should still be warm enough to swim in the Cinque Terre, only a couple of hours from Florence. Plus, there's beautiful walking to be done there.
Let me know if you need price-conscious accommodation referrals in any of those places. Buon viaggio!
Pietro di Ponte
(Wishing I were in Siena)