Husband and I are planning to travel to France, Switzerland and Italy for our honeymoon. Is this too much travelling for a honeymoon?

Our itinerary: 4N Paris 2N Lucerne 1N Milan 3N Florence 3N Rome

Our idea of a romantic holiday: Relaxing with a beautiful scenery and enjoying exotic cuisines and dining experience. We would love to visit some Iconic tourist attractions as well.

Questions: -We would like to enjoy a cruise/ferry experience, where should we get that? -Can we get a CONVERTIBLE 2 seater merc/luxury car in Lucerne? -How much budget should we keep in mind for 2N in Switzerland? 3 star hotel+food+sightseeing -What’s the best train to travel from Paris to Lucerne and then Lucerne to Italy with comfort and wide windows for view? Is there a water travel option/ferry? -Offer me some changes in our itinerary as honeymooners. -interlaken or lucerne?