How much pre-cruise time are you spending in Rome?
Orvieto and Umbria - I have visited both; Umbria from memory is a 2 to 3 hr train ride from Rome. These timings may have changed since my last visit. Orvieto has a great cathedral and very interesting place to visit. A must do is the Orvieto underground tour. Fabulous wine - but of course that will be of no interest.
Train to Lucca is very easy - which port?
Here is a link to the Italian rail system