I went to Oahu for two and a half weeks at the end of May 1997. It didn't seem 'busy' anywhere except when we visited Pearl Harbour. My 2 children and I stayed with friends on the Army base and Karen was our personal guide. The school term had a week to run so that might be a time to aim for... Reading through the above posts makes me want to travel again... maybe drag the 'old man' this time; he couldn't get time off back then.

Pali lookout, the Sea life centre, Turtle bay, the pineapple farm, Hanauma bay, 'Pearl', the cemetery of the pacific ( well worth a visit) and Diamond head... and as reminded above.. Waikiki and Hale Koa, brilliant pools if you don't fancy the surf!! Happy memories.

Go - enjoy! I doubt you'll be bothered by mega crowds - everyone was so laid back
Hx