Hawaii
 

Will be spending 4 days in Honolulu, a week in Kuwai and a week in Mauii. First time to Hawaii. Other than Pear Harbor, any must do's you can recommend on any of these islands? thank you

Kanapaulli Beach Maui Not sure of spelling It's beautiful We are from upstate NY GUILDERLAND

I really enjoyed the Polynesian Cultural Center on Oahu.

On Kauaii don't miss the Napali coast or Waimea Canyon. Just returned from a month there. Napali Coast locations were used in Jurrasic Park, Raiders of the Lost Ark.
Where was Jurassic Park & Jurassic World filmed: Kauai Island ~ Atlas of Wonders

Stationed in Hawaii in the military for five years
 

We recommend seeing Waimea Canyon on Kauai; it is beautiful. There is a lot of pretty scenery there. The north shore is also pretty beyond Princeville.

On Maui our favorites were driving the road to Hana; it is very curvy along the ocean; breathtaking scenery; a two hour drive each way. Also going Haleakala National Park is worth seeing. Sunrise is supposed to be breath taking, but we never were up there at sunrise. It is quite chilly at the top of Haleakala.

We lived on Oahu for two years, and I have a few favorites...first of all, if you're wanting to do a little boat tour, the E'O Waianae dolphin tour is the best you can do! You get to swim with wild spinner dolphins, snorkel with sea turtles, etc...it is owned by a local family, and they are wonderful...call 808-699-5910 to book. They do pick up in Honolulu to shuttle you to the harbor over in Waianae...
Visit Ko Olina....four man made lagoons, Roy's Restaurant is on the golf course...a great luau is there, Paradise Cove...an amazing place to eat right on one of the coves, which used to be called Longboards...not sure if it still is...Go to the little surf town of Haleiwa....cute shops, places to eat...Kono's is delicious...go to Waimea Bay...beautiful beach...across the street from the beach is Waimea Falls...you can "hike" to the waterfall, which is about a one mile walk on a paved path...I think they also have a little golf cart shuttle, as well. You can swim in the waterfall...just east of where you will be staying is Hanauma Bay...amazing snorkeling...heading around the island, you will see where they filmed some of From Here to Eternity....the beach is called Secret Beach, although, you can see if from the road...and, it's right by the Blowhole lookout center....there is a great "hike," right up the road from the Blowhole lookout, called Makapuu...pretty mile hike...uphill...lighthouse at the end...great view of Chinaman's hat at the top....the Polynesian Cultural Center is okay...make sure to visit a Shrimp truck while heading up north...on the way to Turtle Bay. We liked Giovanni's the best.
You NEED to try the malasadas at Leonard's Bakery. In Honolulu...and, there are a few Leonard's Jr. trucks on the island, as well.
Maui...visit Haleakala Crater (like someone else said, it is very cold...kind of freezing, really. Take a sweatshirt)...I loved the Alii Kula Lavender farm...Visit the Ulupalakua winery...gorgeous...Iao Valley park is beautiful...
Kauai...Waimea Canyon, Na Pali Coast...Kauai is very laid back...You will have a great time...everywhere you will go will be beautiful!

Sophie said it all way better than I could. We moved here to TV from Hawaii (Oahu) after 25 years there and my husband born and raised there but that's neither here nor there. Follow Sophie's advice and you cannot go wrong. If you do, you will have the vacation of a lifetime.

Enjoy
 

Consider visiting the historic Iolani Palace in Honolulu. Built in 1882 by King Kalakaua, Iolani Palace was the home of Hawaii’s last reigning monarchs and served as the official royal residence and the residence of the Kingdom’s political and social life until the overthrow of the monarchy in 1893. It requires tickets, which are best bought in advance. Limited number of visitors per day.

Home - Iolani Palace

Pali Overlook. Five miles outside of Honolulu. Free. Magnificent view.

Pali Lookout - Nuuanu, Oahu | GoHawaii.com

Hawaii
 

If you have time, before you go you might want to read James Michener's fictionalized account of the history of Hawaii in his book Hawaii. It is loosely based upon the actual early history of Hawaii, from the days of the Missionaries and Whalers up through modern times.

It gives a great appreciation for the culture and diversity of the islands.

You might skip read through the first chapter or so which is just about the geological development of the islands.

The Missouri, if it is still there. The ship where Japan signed the surrendar documents to end WW2.

On Kauai don't miss the helicopter ride into the volcano, Kauai Helicopter Tours | Kauai.com

boat ride off the Na Pali Coast - Na Pali Pirates Zodiac Raft Adventure Tours Kauai

boat ride up the river - Kauai River Kayaking | Wailua River, Kauai, Hawaii

Have fun

if you go to hanauma bay for snorkeling , bring a loaf of bread to feed the fish when snorkeling lots of fun.

Mama's Fish House on Maui
 

On Maui: For a fine dining experience at a local famous restaurant, visit Mama's Fish House Restaurant. Expensive, but the atmosphere, location and food can't be beat. Not too far from the airport, and near the beach where all the kite surfers can be seen. Make a Reservation! Mama's Fish House Restaurant | North Shore Maui Hawaii One of our most memorable experiences of our week on Maui.

Clifton Park.

My favorite place on (near) Maui is the islet of Molokini just a half hour boat ride from Lahaina Town. It has the best snorkeling I've ever experienced, but you can enjoy it even if you aren't a snorkeler. Google it for some spectacular photos. Another suggestion is to check out Tripadvisor for comments on the road to Hana. Mixed reviews for sure. I made the drive some time ago and when I finally arrived, I wondered why I put myself through the long trip. There isn't much to see in Hana.