I am going in Nov, plan to see Oahu, Kauai and Hawaii (Big Island) in 2 weeks, I know that's a rush but its all the time I have.
Wont be doing any snorkelling etc as I live near the reef here and do that pretty often. So that saves time. May do the Manta Ray snorkel but.
RAM I want to do Mauna Kea right to the top, I read people who say you don't need 4wd, some say only 4wd rentals beyond the Visitor centre. Other say you will die, don't go.
There should be tours that'll take you up there - can try to find out by emailing or looking at local hotel's web pages like the King Kamehameha hotel at Kona. I would not risk it without a 4wd. The Saddle Road is fine in a normal car but if anything went wrong on the mountain road then you would be looking at big money. Take a very good (warm) jacket & gloves.
Mauna Kea Summit Reviews - Kailua-Kona, Island of Hawaii Attractions - TripAdvisor
Visiting the Summit - Maunakea Visitor Information Station
The only company I have found who say it IS OK to go right to the top is Harpers.
Have seen videos of the road and doesn't seem too extreme apart from altitude unless wet/snowy in which case it would be closed anyway I guess.
So will give them a go probably.
Any tips for chopper flights over the lava/volcano area?
We tossed up chopper vs light aircraft - went for an 8-10 seater light plane from the Kona airport - more room, not so noisy, and we liked the result. Supposedly can be better opportunity with fixed wing due to air currents but who knows. Cost was similar between the two but plane went a bit longer. Covered the whole island, guess about 2 hours of flying. Just near the airport, next turning off Queen K Highway are the energy labs - generates power by putting water down a 1000s metres long pipe etc - quite interesting if like science.
Inside Kona’s Natural Energy Lab
Is South Point worth a look?
If you do the 'circle flight' or island explore flight in the first day or two then you can get an idea of what you like the look of. Plan from there.
Also want to see Capt Cook Memorial where he died at Kelakekua Bay, some say kayaks are banned now and you have to hike in.
I may be wrong (don't think so) but we drove in to a car park and then walked only a few hundred metres. A good number of the areas are 'sacred sites' so you must obey the signs. The 'Place of Refuge' can be quite eery.
I guess a lot depends on weather at the time...