Third cruise-ship visit to Hilo; not interested in overpriced tours. Decided to visit Tsunami and Lyman museums downtown. Paid $15 for the (brand-new) HOHO bus, which was overwhelmed by having two ships in port and not operating exactly as advertised. Bus dropped us off downtown, where we walked around and to both museums. Then continued the 50-minute round trip.
We were told by others that taxis are expensive in Hilo. This is a small place (35,000 in total) where everyone is very friendly and helpful.
We walked (less than half a mile) to the historic Iolani Palace and took a one-hour guided tour ($22 each) with a very informative docent. Then we watched a free concert by the Royal Hawaiian Band before boarding the HOHO bus ($17 each) to visit Diamond Head and the interesting Honolulu Zoo.
In many years of travel, we've never taken a better tour. Ellen, Dori and pilot Josh (and Millie the dog) at Wings over Kauai treated us like old friends, operated with great efficiency and provided a stunning tour of the beauties of Kauai, all at a price half or less than what you'll pay for a tour by helicopter. On this fixed-wing plane, a window seat is guaranteed.
Third cruise-ship visit to Lahaina. Took the public bus ($4 each, all-day) to Maui Ocean Center (saving more than $100 vs. a ship's tour) and to the mall in Kahului, then along the coast to Ka'anapali and back.
We found this mode of travel to be pleasant and relaxing, with lots of scenery. You don't get commentary, of course, but the bus drivers are friendly and helpful.