It is located in Ko-Olina, in the Northwestern part of the island. It is about 45 minutes from Waikiki. I was there last year, staying at the Marriott resort, before Aulani opened. That is considered a "resort" area but as of last year there wasn't much there. touresty, other than the Marriott, golf course and a few restaurants.
If you go I suggest either booking tours that pick you up from the resort or renting a car. We had a car and drove everywhere, even down to Waikiki a couple of times.