Check Costco for discounted tickets, call to make reservations in advance. If doing helicopter rides, don't go for the cheapest one. I think Air Maui has one of the best safety records.
This place is whatever if you follow the rules and just look at the needle, BUT after looking at the needle walk back down, and walk towards the stream near the garden area.. there will be a sign that says "do not enter".. you should enter and follow the trail. There's lots of entrances like that so don't worry about finding the right sign. Parking is $5. The trail takes you along side the stream.. You will smell guava flowers or guava fruit.. when you see a good spot for you to climb down to the stream, do that and swim. When you see the stream you'll understand why - its totally safe and its like mother nature made you these little swimming pools in the middle of the stream.
Sunrise is amazing, but you have to wake up really early and it gets crowded.
It's still a fun drive regardless, and really unique up top. You can also rent bikes. There are theres silver sword flowers that only grow there and are endangered.. and these things only bloom once in their lifetime