Be thankful for the mainlanders, I mean come one, your economy is mostly based on tourism, a small finance sector and some construction, that's it. Without washington you'd fall back into... well, look at Cuba now, and island without american tourists and without american gov.
I've never been to Hawaii nor am I an American (yet...), but from my outside view Hawaiians only benefited from the union. BTW, you got one of yours in the White House currently, and his predecessor was - speaking about environment - a conservationist who also took care of Hawaii.
Besides a stable government, military protection from the world's last and only superpower and a stable political system that allows every Hawaiian citizen to achieve whatever he wants, your people live in freedom and can do whatever they want. And no, the rich tourists - many of whom are very influential - won't let Hawaii secede, get that idea out of your head.