Welcome to the board, firenz. We usually take the Regent excursions rather than working up our own (we're inexperienced at that but getting better). Like Karen, we took their Pompeii tour and loved it.
Port intensive cruises can be tiring. Pace yourself between days with long excursions and days with short ones. There's so much going on the ship at night that you want to save energy for that fun, too.
Lots of experts here and I'm sure you'll get great advice. Have fun on your cruise.