Florence 4 nights

With 4 nights you basically have 3 full days in Florence. At most you have time for one day trip because 2 days will certainly be needed to see Florence (and just some of the main sights).
The options for day trips are numerous, however of the ones you mention Montepulciano is too far to do as a day trip.
These are the easy choices:
1. Siena (75 min via bus or 90 min via train)
2. Lucca+Pisa (sort of a loop, Lucca and Pisa are close to each other, both about 1+ hour via train from Florence).
3. Arezzo (45 min from Florence) possibly coupled with Cortona. If you do both, do Cortona, the farther, first, then Arezzo on the way back.
4. Pistoia (30 min from Florence via train along the Florence Lucca line)
5. San Gimignano (about 1 hour via two buses. Bus change in Poggibonsi)

In addition to the towns Roberto mentions, here are 2 good organized day trips.

6.5 hour afternoon trip.

https://www.getyourguide.com/florence-l32/chianti-wine-tasting-half-day-tour-from-florence-t4433/?referrer_view_id=de7e7f299af35d61b69f86691d6bd609&referrer_view_position=5

And a full day 12 hour trip.

https://www.getyourguide.com/florence-l32/montalcino-pienza-montepulciano-enogastronomic-tour-t59777/

Another option: a very easy half hour #7 bus ride from San Marco up the hill will take you to the beautiful town of Fiesole.
Fun to walk through the small town and there are a few things to see. You can visit the Duomo and archaeological museum and then a 10-minute hike up the hill to enjoy a beautiful view of Florence. The Bandini Museum is covered by the Firenze Card. We had lunch at Fiesolano. Wonderful veal-stuffed zucchini blossoms and taglietelle with mushrooms.

Thanks for the great ideas the tours look great. We are not huge museum people but love walking around and looking at architecture and cities! Also would love a good wine tour or thermal spa day!

Both of the tours I mentioned include either wineries or tastings.
Scroll down and look at descriptions.

Four nights in Florence gives you three full days there. That is about what you need to do Florence, especially if you go to the Uffuzi and Academia Museums. You many not have time to go to Siena or Pisa.

We took the Tuscan Trails Chianti tour in 2014 and had a great time. Todd is the history teacher you wish you had in high school. Check it out.

http://www.tuscantrails.com

If you're looking for a spa day, head to Montecatini Terme. 45 min by train from Florence. One of the most beautiful spa towns in Italy.

Pictures you find on the web don't do it justice.

any opinion on going to san gimignano is it extremely crowded in may? how much time would we need there? Anyone recommend doing a cooking class tour from Florence to learn how to make pasta. I think some group sizes are max 26 people.

Are you looking for something totally different to do ? Do either of you like sports cars ? There is a Ferrari test drive you can take with a tutor to Fiesole. Rates vary on depending on the length of the drive you want to take take: http://www.testdrivefirenze.com/

my husband would love that test drive. would i be able to ride along? how would we get back to florence?

Yes you can go along for an additional €20. Looks like the longest drive is about 13 miles at a cost of €260 + your 20

Roberto da Firenze , Are the busses to San Gimignano leave early in the morning and leave frequently. Ideally I would like to take an early 6 or 7 am bus and try to get there and spend and hour or 2 before all the other tourist come? Thoughts anyone? I really would like to spend one day traveling around to see these other villages. In an ideal world I would love to spend one day and travel between san gimignano in morning, bike ride around lucca, and see arrezo and greve. I know it be a long day but I would totally love this is if could find a way to see all or most of this in one day