Personally, I think you are setting yourself up for failure with that plan. You're arriving at 2, but you're not going to be off that airport property before 3. Aulani is our home property, so we are there at least once a year. I speak from experience when I tell you that you need to bring your patience with you when picking up your rental car. They are slow, and rarely efficient. I've used every company in the complex at this point, and it's always the same. So, if you're out by 3, you're then battling traffic to get to Pearl Harbor (weekday traffic in Honolulu is on par with what I deal with in Seattle
). Also, you really need to get your tickets in advance for Pearl Harbor. As someone else mentioned, you'll also have your bags in your car, and car prowls are the number one crime on the island. I just wouldn't do it. Land, get your car, go to Target or Costco on your way to the resort, get settled, and relax. Plan Pearl Harbor for another day when you are not rushed and exhausted from travel. Pearl Harbor deserves your time, and after a long day of travel, plus being late in the afternoon, no one is going to want to spend 3 hours there. Schedule your return trip around the days the Aloha Swap Meet runs to grab your souvenirs!
http://www.alohastadiumswapmeet.net/content/home.aspx