My wife and I took a two week vacation in Hawaii last July (her dream vacation). We chose to see a variety of islands, so we stayed 3 nights each on Kauai, Maui, Hawaii, and Oahu. Having done that, we both agree we probably should have tried to get to fewer islands and spent more time on the ones visited. Getting around to see everything we wanted to in just a few days was more hectic than we wanted.
You are planning a summer trip like ours. In your research, if you want to get surf shots and especially surfers, plan on the waves being on the south side of the islands. The really large waves Hawaii is famous for happen in winter on the north side. I wouldn't bother touring the north side of Oahu where the legendary surfing beaches are (Waimea Bay, Banzai Pipeline, etc.). The water was the calmest we saw in our 2 weeks!
I took a 70-300, and it was adequate for surfers on Kauai (beaches on the southeast side of the island) because the waves came well in to shore. Shots on Oahu at Waikiki were less successful - the waves are distinctly farther out.
On Kauai, Waimea Canyon and the northwest corner of the island have the spectacular scenery. You should consider taking your macro - they do have a lively assortment of flowers there. Everywhere. There are world-class arboretums on some of the islands.
Maui - we stayed on the west (dry) side and the sunsets and the beaches were excellent. The road to Hana is amusing but time-consuming, moreso because of traffic than the curvy road (which was bad enough). None of the waterfalls are big and impressive, but there are good shots to be had of them and of the coast as well. In the small, small town of Hana, there's a restaurant that offers an average hamburger for $15 and will probably be crowded (expect to wait to be seated). There is also a grocery store where you can get do-it-yourself lunch stuff. There's also a community beach park on the water that has a hot dog stand on the edge of the beach. It has decent food and reasonable prices and serves it customers much faster than the restaurant. Why does this matter? Because you have to drive back from Hana, and it's slow, and late in the day the people who live in Hana will be coming home from jobs in other towns. The way they drive that road, and their disregard for tourists on the road, will elevate your blood pressure. Better to get your return trip under way early.
On Hawaii, the volcanoes can occupy as much of your time as you care to invest. We stayed in a Hilton resort on the west (dry) side and were very surprised how many others staying in the resort were there vacationing from Hilo, on the wet side of the same island! On the west side north of Kona there are lava tubes at the roadside that offer interesting photo ops. It was surprising how eagerly people jumped down into them to walk through, when caved-in tubes were everywhere around the ones they walked into.
On Oahu, we visited Pearl Harbor, of course. We chose to see it on a tour we paid for rather than do it on our own. The amount of walking is significant, and I'm disabled, so the tour group approach was definitely better for me. We also stopped in and took a tour at the Dole Plantation (halfway up the island from Honolulu) and enjoyed it. We then drove to the north shore to find no surf at the famous surfing beaches. The drive back to Honolulu on the east side of the island was beautiful and offers plenty of scenery. It isn't standard tourist country - it's all residential, so you won't find touristy restaurants and such (that's a compliment).
Gear: when we went to Alaska for my dream vacation, I took a ton of gear and used it all. But this was my wife's vacation, so I took only one body (D7000), my 16-85, and the 70-300G (not VR). The only limitation I had to accept was the 70-300; I wished I had my 300/4 and TCs for the surfing, but otherwise I used the 16-85 exclusively. I can't handhold a shot very well anymore (30 years of arthritis will do that) and I certainly didn't want to drag a tripod around. I bought an inexpensive hiking pole in a local store (Sportsman's Warehouse); it has a knob on its upper end that unscrews to reveal a 1/4-20 thread I could screw into the camera. I found I didn't need to use that screw - I could rest the camera on that knob and get adequate support. The pole adjusts as high as eye level for me, so it was a big success. Anytime we stopped so I could get pictures, I left my cane in the car and used the hiking pole adjusted down to cane length for walking and adjusted up for shooting.
