Never fly to any Italian airport unless you have obtained a positive confirmation that either PPR is not applicable, or it has been approved, for the full details of your flight (non Schengen departure etc). The b*ggers will refuse a landing from a short final if they feel like it, and send you off to your alternate (which might do the same if you didn't get PPR there also).
Same for avgas - nothing happens twice the same way in Italy
A handling agent should sort this all out, if you use one.
But beware the Italian avgas trick where they say avgas is available but when you land you discover they can sell it only to their local aeroclub (a bribe might fix that, if you can find somebody who can smooth the process). Therefore, check this specifically.
Frankfurt has a minimum overfly level of about FL130. Not applicable if you are landing there of course
Not a problem otherwise.
Should be a nice trip, especially if you have oxygen (a bit hard to fly Eurocontrol routes otherwise) and crossing via Switzerland. Spectacular scenery.
Frequent flyer you have a PM.