Hello!
We'll be driving early on a Tuesday morning from Florence south on the N222 with our ending destination near Sinalunga. We want to enjoy the views, do a few wine tastings (no tours due to time constraints) and have a nice lunch somewhere. Here are some villages we'd like to see, but are we trying to do too much before dark? Are there must do's you would add? Some to eliminate? Thanks!

Greve
Panzano
Volpaia
Castellina
Monteriggioni
Radda

I think seeing Panzano and Castellini would fit the bill and not take all day. Plan lunch in Castellini---there is a place with " Torre" in the name we liked.

Here it is: http://www.anticatrattorialatorre.com/

The Le Cantine di Greve for wine tasting would be a good choice for getting a great feel for all of the Chianti wines and many from around Tuscany and even other regions.

They use a smart card system for tastings and offer food snacks and olive oil.

http://www.lecantine.it/cantineUtente/degustazione.php

We were a little underwhelmed by Panzano. The views are gorgeous, but the town (a weekday in October) was as quiet as a library. Wandering tourists outnumbered the locals we saw by about 5:1. Nothing was open except the church and the small bar/cafe opposite.

South of Panzano, I would make a detour off N222 to Radda and then back to N222 at Castellina, Radda itself not being the goal (althought it's nice enough) so much as the scenery.

We had a nice lunch in Radda at Le Forchette del Chianti on via Pianigiani and also a good lunch in Castellina at the same restaurant bobthenavigator recommends. You should plan to spend some time in Castellina exploring the town and doing a little shopping (spoken by someone who doesn't like shopping!).