I suggest you do some observing with the Hawaiian Astronomical Society at Dillingham Airfield.
http://www.hawastsoc.org/
The bus fares for a trip around Oahu are very cheap. A 4 day pass is $20.
http://www.thebus.org/default.asp
If you can get to the Big Island you can see the Keck Telescope with two 10m mirrors and you can also see hot lava flowing into the sea.
http://astro.nineplanets.org/bigeyes.html
http://www.ifa.hawaii.edu/mko/
http://volcano.wr.usgs.gov/hvostatus.php