It depends on your preference. If you are staying on the island for a while, I highly recommend renting a car. Another alternative is to use taxi or bus services!
Beach formal is the desired attire! The grass is soft. So maybe rethink stiletto heels!
I provided a list of recommendations under the section "Travel". You can also use Tripadvisor!
The month of March in Hawaii averages with sunshine and a temperature of 80-85 degrees!