I know there are fairly frequent trains...you might want to check the Trenitalia site to see times:

http://www.trenitalia.com/en/index.html

Suitcases shouldn't be a problem if you aren't arriving last minute - there's usually space. Just keep an eye on your bags during stops/transfers.

Although I've never driven, I imagine you can rent a car, but you probably want to drive between cities and not into them.