In Hilo it seemed like *everyone* booked the Volcano excursion. I didnt want to be around a ton of people after spending 5 days @ sea, so I opted for theHawaii Tropical Botanical Garden. It was so wonderful and gorgeous... a real nice, paradise escape to just enjoy nature and go for a nice walk through forest surrounded by ferns, palms, etc.
I highly recommend going to see it. It was quite reasonably priced too... something like $35 including admission AND a shuttle bus from the pier to the gardens and back again.