Honolulu. Waikiki. Oahu. All the same to most tourists. That's okay. Many areas in Oahu are Honolulu. One of my favorite's is the Diamond Head Lighthouse, off the road below Diamond Head.
This lighthouse may not be as famous as the lighthouses in Cape Cod, but the location, setting, and view is oh, so much better. If getting out of your vehicle be careful. The road is narrow around the base of Diamond Head, ocean side.
As you wind around Hawaii Kai, go past Hanauma Bay and go past the golf course, you'll start to climb up a long straightaway toward the "Blow Hole" and Makapu'u. You'll see cars parking on the side of the road near a gate on the right side of the road. Park (secure valuables) and take a stroll through the gate to the Lighthouse. Beautiful view. Easy stroll (slippers OK, tennies better, boots not necessary). But go early...hot you know.