walking tours florence (travelling with teens)

I will assume you are starting at the Train station? From there, I would find the Medici Chapel / San Lorenzo and walk towards that while going by the Church of S Maria Novella. There is typically a market outside of here. The goods are hit/miss, but it's a festive atmosphere. Tour the Medici residences (or don't) and move on towards the Accademia. It's small, even if they don't care about David (and it's pretty impressive in person), you can promise them a half hour or less and probably not be lying too much. Work you way back going by the Duomo and the Baptistry. The Duomo is certainly worth going inside for and can be done pretty quickly. Continue heading south, to your right will be a big piazza (Repubblica) with lots of restaurants, straight ahead will be Piazza della Signoria and the corresponding Pallazo. Detour to Piazza Repubblica or continue ahead to the Piazza Signori. Lot's of statues and fountains here, pretty cool plaza in general. From here, you can continue on to the Uffizi. I would consider either skipping it or giving your kids 20 euro each and meeting them back at the entrance in 1 1/2 hours. It's a big museum that could try the patience of a fully rested adult. They do have an awesome rooftop cafe, however. Continue to the river, hang a right, toward Ponte Vecchio. The bridge is home to a bunch of jewelers (overpriced, I've heard) but is still a fun site.

(cont) Continue straight ahead. On your left will be the Pitti Palace. If your kids are complaining, tell them you can have their Pitti party there. Turn right (on a map, look for Santo Spirito and walk towards it). You should stumble on a place called Gusto Pizza. It's the best we had in Italy and kids love pizza, right? Eat the pizza in the Piazza Santo Spirito and then head back to the train station. Try to go via the Ponte all Carraia bridge. According to some locals we met, the best gelatto in town is at the Al Carraia Gelatteria on the southern entrance to the bridge (We agree)

Thanks Ken! What a great day this will be!!!

Ken's suggestions are spot on. Including that Gusta Pizza - delicious. I might suggest, for the teens, is to climb the Campanile for an awesome view of Florence. Maybe they could climb while the "older" folks tour the Duomo or Bapistry

Here's the only thing Ken forgot:
That's to seek out the Il Porcelino boar statue/fountain in the Mercato Nuovo, very close to the Piazza della Signoria. Its exact replica has a home in the Butchard Gardens in Victoria. The popular thing to do is to place a coin in its snout and let the water slide it down. Rubbing the shiny boar's nose is supposed to ensure your return to Florence. It's a very cheesy, very "Florence" thing to do...