I'm an OOS'er who's going to be in town for interviews from 12/17-23rd. What exactly can I do as a sightseer during my abundance of free time? I'm going to be travelling alone as my GF doesn't have the money for the flight. I know there's a lot to do in Hawaii but not sure how to go about it by the solo route[/QUOTE
Have you never been to Hawaii? What did you say on your application to get an interview here if that is the case? Anyways, depends on what you like to do. So what do you like to do?!?
If you like snorkeling in December then Hanauma bay will be your best bet. (Shark's Cove and Electric Beach usually are too dangerous to visit with the winter surf)
If you like hiking some easy one's you can do are Maunawili Falls and Koko head. If you want a little more challenging of a hike do Olomana. There are hundreds of other hikes but I wouldn't recommend you go on those alone (many people get lost or hurt). That said, some of my favorites if you make some friends are Ka'au crater and Mt. Ka'ala.
Some pretty popular tourist attractions are Pearl Harbor, Dole Pineapple plantation, Waikiki, Haleiwa, Sunset Beach/Pipeline/Waimea (beach and canyon), Polynesian Cultural Center, Pali Lookout, Sea Life Park, the Zoo.....
Now to what really matters: Surfing. If you don't know how to surf you need to learn how to surf. If you don't know how to surf, go to Waikiki and rent one of those huge 12 foot boards (they are blue) and use it to learn to surf. I have taught many a mainlander how to surf on those boards. Have someone show you how to get up on a board (on the beach) and then practice catching waves and getting up. You can learn to surf in as little as five minutes if the waves are good and you have a rough idea of what to do.
Also, take some time to talk story with the locals. As above&beyond has made clear, you can get around the island to most places by bus if you haven't rented a car (take the 55 to North Shore). Some of my best conversations have been on the bus. You can use google maps on your internet phone assuming you have one to know how to get around on the bus along with the locals and bus drivers who are usually pretty helpful. Have fun!