Delta give a bit more info. When you say escorted, do you mean some kind of package deal? What type of websites are you referring to? You can arrange a very nice package yourself and the fun can be in the planning as well as the travelling.
One suggestion: fly Ryanair/Aer Lingus to Berlin, spend a couple of days there,(DB/OBB) train to Vienna, optional travel to Salzburg/Budapest. Bratisalva is 40 mins from Vienna Sudbahnhof. From Vienna travel (tranitalia or OBB* ) to florence, you can catch a bus from here to Sienna if you feel up to it, then to Rome & fly back Aer Lingus.
DB: Deutsche Bahn (Die Bahn)
http://www.bahn.com/i/view/index.shtml
Osterreich (Austrian) Bahn (OBB)
http://www.oebb.at/en/
Italy: TrenItalia :[broken link removed]
If you opt for this, get a sleeper from Vienna to florence, it's a longish but nice journey. You don't usually need to prebook, but you might in high summer.
A nice central hotel in Vienna is the Hotel Regina near Schottenkirche & Schottentor. (train station/underground). Can highly recommend Vienna, I lived there for a while, it is a stunning city and should not be missed. Bratislava is ok for a short visit, but I would give it a miss if your pushed for time and visit Budapest or Saltzburg instead.