In my experience, if you are hoping to save a few bucks by seeking out cheaper parking you are in for frustration. You'll end up doing a lot of driving around and spending a lot of time hoping for a space to develop and more often than not you'll end up 10-15 blocks away either hoping you read the parking restrictions correctly or schlepping back to move the car and repeating the whole dance again. Either plan a little extra and use the hotel parking, or do the rent-for-a-day thing (the Alamo/National locations a 5 minute walk away on Ala Moana usually has better rates than the on-site Hertz)