Hi~~I have done a the Hawaii cruise RT from San Diego with Holland America, and have a 2nd one planned for April 2008.
DH does not fly, so that's the only option for us. It is 4 sea days over and 4 sea days back, but if you plan activities, you won't get bored.
HAL has a wonderful cruise, and yes many passengers are older, but that doesn't bother us.
We cruise for the service and food, and HAL excells in those areas.
It is an expensive cruise but SO worth it.
Have fun !!