You would fly.
See the NPS website and the Top Questions about Pearl Harbor. (TQs are on right side of page on O`ahu forum.)
Marie, if you haven't yet bought tickets, then I would stop on Oahu for a night or two before going on to your other choices.
How long is your trip, total?
How many days will you have on Maui? On Kaua'i?
Have you booked your flights?
If not, you could fly into HNL or out of HNL from the mainland (or wherever home is) to potentially save some $ on airfare costs. Check the options to know for sure.
Marie, where are you coming from? It can make a difference for flights.
fishdiva, you beat me to it!
I would not contort your trip. Either give Oahu five days minimum or skip it altogether this trip.
Oahu has a great deal to offer beyond Pearl Harbor!