We did Hawaii on Infinity in April. We spent several days pre-cruise in Honolulu and had a very enjoyable time. We only rented a car one day. Had planned to visit Pearl Harbour on our own - however, heard about the LONG wait after getting ticket. We elected to take a 1/2 day tour through Celebrity the morning of the cruise. The bus picked us up at the Hyatt and first took us to Pearl Harbour where the driver got our tickets for us (it was either 2 1/2 or 3 hour wait from the time he picked up our tickets!). He then put us back on the bus and we toured some of the sights we had not seen when we had the rental car. Then, at the "appointed time", he returned us to Pearl Harbour and we were just in time for our number to be called! Was pretty cheap tour - can't remember the price - but it was the only shore excursion we purchased during the entire trip and we were glad we did it simply because we didn't have to wait around at Pearl Harbour for our number to be called -
Enjoy your cruise.