1. Honolulu, KoKo Head Hike

  (Wake up at 4am and hike this trail for an incredibly rewarding Sunrise up top, it's a tough hike,    but you will get a butt lift after, I promise! 

2. Maui, the Hana Drive

(breathtaking views and hard to drive road, recommend renting a jeep for this route) 

More to dos:

Maui

1. Lavender Farm (good tea and scones, their cooking salts work well on fish as well, book ahead to get a guide to walk around with you to explain things. better than wandering yourself not knowing what you're looking at)
2. T Komoda Store, delicious bakery. nice stop on the way back from the sunrise.
3. Wailuku/Kahului, I'ao needle, short walk and nice view, with plaques describing the historical significance of the site 
4. Okay, beach wise, Ka'anapali. If you are daring, you can jump off black rock (which is fun).
5. Out south past Kihei there's Makena Beach Park / Big Beach / etc

Waikiki, Honolulu 

BEACHES there's waikiki, its going to be super crowded, here are some others

1. Hanauma Bay one of the prettiest beach areas out there, really cool bay/cove thing going on 
2. Sherwoods/Waimanalo, on the way to Kailua, in between there and Hawaii Kai. Really pretty, not dangerous like Sandys
3. Kailua Beach Park really nice out on the windward (eastern) side of the island. Really beautiful picturesque beaches. 

Hiking

1. Diamond Head pretty standard, just one stair section is pretty steep but good views and a nice light workout
2. Makapuu Lighthouse Trail pretty easy, good views 
3. Manoa Falls, not too bad, relatively short, not good if its raining (gets muddy)
4. Koko Head, a.k.a. the stairmaster, this is a big workout. only takes up to 2 hours total but its a beast (like 1000+ stairs)