Travel options from Rome to Pasitano on AC? Is there a bus service from Rome to AC?

What are my travel options from Rome to Pasitano on AC? We ( 3 adults) are flying into Roem then going to AC for 4 days and flying into Venice for a cruise on the 19th September. Can we leave a large bag at the Rome airport in a locker for our trip to Indian and Bhutan, as we don't want to lug that bag all over Italy. Thanks.