From one end of Waikiki to the other is a decent walk, but very doable. There is shopping all over the place, tons of restaurants, you may come upon a "mime" doing his or her thing on the sidewalk. Watch the surfers, the outriggers, the paddle boarders, and the boogie boarders as they ride the waves; relax on the beach watching the waves, the sunrise over Diamond head, the sunset; take a dinner cruise--there are so many things to see and do once you arrive in Honolulu, but first things first, get to your hotel and relax!! for 30 minutes at least.
So many people on the streets at night its pretty safe as long as you keep to the main drags, there is a variety of life out there from old timers to hot party girls wearing - well not a lot :)
There seemed to be a few homeless trying to get some sleep around the beach fronts from what I seen but you are left alone to do your own thing. All in all I would quite happily go back.