So I found a deal to Hawaii from Detroit for $360 so I got it! We'll be in the Big Island for 7 nights (3 in Kona, and 4 in Hilo but I'm flexible on this) and 4 nights in Kauai. I would love to hear tips to make it "MMM approved". We are going to stay in Airbnb's that includes a kitchen so we can make some of our meals. Car rental prices seem extremely expensive-- even more than Iceland.
Great deal on the airfare! You will have a wonderful time. We went last summer from June 25-July 4th. I bought a package through Orbitz with air, condo, and car for just over $4,000 for 4 of us. They upgraded the car for free to a Vespa and there were only 2 times more power would have been needed to go further on our trip.
Food is more expensive, but like you we made several meals. We had great luck buying from the local farmers markets and cooking at home. Lychee's were a real hit for our family. Several fruits I have never seen and were fun to try.
We didn't even try to "see it all", and we didn't. There is plenty to see and do without spending a lot of money. We stayed on the Kona side the entire time, with the exception of a 1 day trip all the way around the island, and day trips to specific locations. It was a long day around the island, but nowhere else in the world can you visit 10 climates in a day. It was amazing. We saw and greatly enjoyed a lot of things on the Hilo side, but could have spent days there (days EVERYWHERE, in fact). The highlight for me on the Hilo side was the ‘Akaka falls and Rainbow Falls right in town.
When looking, you might want to price places by the week. You might get 7 nights for the price of 3 or 4. For us, EVERYWHERE we went was paradise. We also prefer finding a home base and spreading out as we go, rather than hop from place to place. I think both methods can be great on the big island.
Some cheap highlights you might consider(Focusing on the West side of the Island, where we spent most of our time):
Snorkeling - Free from shore. We bought gear at Wal-Mart. For us just putzing around, it worked great. We lost 1 mask to the ocean, but gained 1 flipper, so I guess the garbage gods might say I am even :( We have a non-swimmer in the family. She skipped Two-Step, but it was fantastic. She was able to snorkel at Kahaluʻu Beach. We stayed less than 10 minutes from there, and went several times. Very shallow and calm in low tide. 1 face to face with a swimming sea turtle. No dolphins for us, but they are in the area regularly. We swam around SEVERAL boats that charge to take you snorkeling. We wanted to hit Captain Cook, but ran out of time. We just left the snorkel gear behind for the next family.
Boogie boarding - There were free ones to use at our condo! Magic sands beach was the best place for us to swim and boogie board. 5 minutes from out condo, great in high or low tide. Great fun, and very easy to get started compared to surfing. I would have bought a board at Wal-Mart and left it behind if we didn't have one to use. I would go a step up from the cheapest or 1 good wave could snap it.
Manta-Ray watching - Again, we were 5-15 a minute drive from a great location. Go to Rays on the Bay at the Sheraton Keauhou Bay Resort in the evening. Stop by for a drink, or just walk around the hotel. They have a lighted viewing area where you can get a great look at the rays as well as look at all the paying ray swimmers. The shores of the big island are public. Privater beaches are not allowed. For this reason, you can enter the water anywhere. If you want to swim with the Rays, just get in the water and swim with them. I was quite content watching them from the hotel viewing area but I would have just gotten in before paying $100 to swim with them after a 100 foot boat ride.
Tour a coffee plantation - Pay tours and free tours are available. If you can not find a free one, ask vendors at the farmers market. We were invited several times to tour the vendors place. We were always "too busy", but we would have loved to meet them there a few days after meeting them. One of the interesting things about the island is that "dirt" is a big deal. Many people grow right on the rock, but if you have soil on your land, you can better grow things on the island. Elevation is critical to what grows where. I have a garden and this would have been a lot of fun to see.
Hiking - One of my favorites was hiking one of the steepest roads in the world at Waipio Rd., Honokaa, Hawaii. When you reach the bottom, you can go right to reach the beach. But FIRST, take a left and walk about 10 -15 minutes to get a good look at Hi'ilawe Falls, the longest waterfall on the island. Then head to the beach, about a 20 minute walk the other direction. Wild horses will as you for some food. A great place to swim, but the current can be strong there, so I would only head in waist high and watch the tide. Heading back up the hill was a challenge. Bring more water than you feel you need.
Star gazing - Drive to the observation center on MaunaKea. 9200 ft. They have planned stargazing nights. To go higher, you need 4wd and a contract from your rental company that says you can go there, or hitch a ride from the center. Our daughter felt funny at 9000 ft, so we did not attempt to keep going. I still loved my time at the center. BRING A BLANKET. We could see moving satellites with the naked eye.
Luau - We thought it was not going to be worth the money. Instead, we went to a free Hula and fire dance at Mauna Lani shopping center. I do not see the twice weekly show listed now. It might be seasonal, so they might return. I thought it was great.
Here is a good link to cultural events, some are free.
https://www.lovebigisland.com/luau-hula-big-island/?highlight=luau We used this site to plan MANY of our days.
Vanilla Bean farm - This was paid and very near Kona airport. I found it fascinating. Very expensive beans to buy after your tour(we didn't). There was another, more expensive tour elsewhere on the island. Our tour was very small, and just our family. I enjoyed it, but at $45 for the 4 of us, it was one of the more expensive things we did on the island. I believe it was worth the money. You might not have the time.
Lava - We went during the great eruption last year. It was one of the reasons we went, figuring people would stay away. We were right. We could not get anywhere near lava without a helicopter. We passed. Locals were very hesitant to point out placed to see lava. It was destroying homes and was considered very disrespectful to go to see the destruction. Ask locals where to go. If it is safe and not destructive they will tell you where to go.
Keep us posted, and return with your results :)
Thank you for reminding me of our trip. It really was one of the few travel destinations where I could instantly picture moving there. It was a site to see.