The Big Island of Hawai'i is definitely about volcanoes and tantalizing adventures waiting for you!
Herein you will find a suggested itinerary which rather than being spelled out per day, I have placed them as experiences which you can sort out as per your needs and time frame.
Airport of arrival:
Experience #1: Hawai'i Volcanoes National Park
Once you exit the arrivals section at ITO airport, you can immediately try to book your helicopter ride with Blue Hawaiian Helicopters and decide on their tours. I went on the Circle of Fire plus Waterfalls and was not disappointed at all.
As you can see from the IG video and aerial photos, the views from above are breathtaking as you fly above and around the craters and lava flows in the area.
On this same path you will reach the Thurston Lava Tube which during my visit did not have the electric power to keep it lit so I (and many others) ventured inside using our phones as torches.
As since September 2017, the lights are back within this lava tube, so I shall return to provide a better view of it!
Once you park on the side of the road, you'll have to walk for almost a mile before reaching the boardwalk where you can learn more about these sacred images sculpted on the lava.
... and as you continue to descend until you cannot go any further, at least by car ...
... you will come across a lookout where you'll be standing at the edge of the world's longest chain of islands, a vast archipelago that stretches far beyond Kaua'i to Kure Atoll, over 2,575 km across the Pacific.
On the horizon, at about 45 km (28 miles), lies the submerged summit of a newest volcano, Lō'ihi. At 969 km (3,180 ft) below sea level, the rays of the sun never reach its summit.
Just around this location, you can walk a bit off road toward the cliff and find ...
This lava sea arch called Hōlei was created in the last 100 years and may not last much longer as the sea continues to erode its base, but for sure another arch shall be formed/created as the waves keep making their way inland as the years pass.
Heading back up to the Kilauea crater ...
Experience #2: Go waterfall hunting
While in Hilo, you definitely have to visit both the Akaka and the Rainbow waterfalls.
The entry fee to the park is $1 for pedestrians, but if you decide to park your car within the premises of the entrance to the falls, you will have to pay an extra $5 parking fee. Otherwise, you can simply park your car on the sides of the road right before entering the parking lot to the falls and you'll save $5.
If you feel adventurous and would like to take a short hike to the top of the waterfall, you can do so, but be very careful.
Experience #3: Head out to some unique beaches