We have done lots of extensions on our Viking cruises.  The Ultimate Italy Tuscany extension is by far the best, most inclusive extension we have done with them.  Almost all meals are included.  Full days of excursions (all included).  Because you are staying in a Villa about 35-40 minutes from Florence, you do not have the long drive from Livorno to Florence.  Thus, you can decide to spend your day ported in Livorno to either go to Pisa (not as far as Florence) or Lucca or go to one of the muse