NO-BRAINER ROUTE: The first way would be to come in from the East via the Hawaii Kai route. Assuming you are coming from the airport, get on to H-1 heading East. Do not get off! Eventually you will pass the fields. Here's how: The highway will end approx 10 miles later and become the Kalanianaole Highway. Continue on the road. The road will go through Hawaii Kai, up past Hanauma Bay, past Sandy Beach, past Sea Life Park, through Waimanalo, and the fields will be on your left (right after you pass the McDonald's on the right, keep an eye out for the fields on the left).
STILL QUITE EASY, BUT FASTER: The second way is still relatively easy. Again, assuming you are coming from the airport, get onto H-1 East. In approximately 2 miles you should see the offramp for the Pali Highway. Get onto the Pali Highway heading North (left at the stoplight). Take the Pali Highway up over the mountains, through the tunnels, and out the other side. Start counting stoplights once ou come out of the tunnel. After the third traffic light, merge over to the right lane so that you can make the right at the fourth traffic light. This road is Kalanianaole Highway. Continue along this road for approximately 6 miles. The fields will be on your right.