Welcome Elmosisu,
in one week only, you have to select the places to visit. You will be there with a motorbyke, car or what?
Anyway, Firenze will take at least 2 days, then going to east coast you can visit Pisa, Torre del lago Puccini and Viareggio and down to the coast: Populonia, Isola d'elba, Follonica and you have finished the week.
If you are with a motorbyke, after Firenze, I suggest you to spend your time in Siena area .
Tanti passano la vita a sognare, io il mio sogno lo guido Colui che segue la folla, non andrà mai più lontano della folla.