Aloha,
I have sailed from Honolulu to Manele bay on Lanai then to Lahaina and then back to Honolulu (via an overnight in Kaunakakai, Molokai), 4 times. It's usually a nice trip totaling about 32 hours under sail at around 5 knots.
I like to sail south from Diamond Head down the West side of Lanai keeping about 2 miles off the coast in order to keep some wind in my sails through the night (sometimes having to heave-to off Kaunolu village to wait for the dawn to enter Manele harbor (anchoring off the harbor breakwater is possible, but lumpy and you can drag anchor if the wind rises).
If you choose to sail between Molokai/Maui and Lanai you may find wind, and you may not find wind, depending mostly on time of day.
I have sailed once from Honolulu to Kailua Kona. I took about 46 hours, and was an adventure! The Molokai channel (at night) was fairly calm, the day-sail west of Lanai and Maui was easy...until we entered the Alinuihaha channel south of Maui. The wind piped up to around 30 knots and the seas got as high as 12 feet. We were on a 29 foot sloop and got drenched... even with a dodger and bimini! It was 10 hours of a miserable (and from what I have heard...normal) channel night. In a pouring rain we were almost hit by a tourist cruise ship (the VHF saved us). Around dawn we entered the wind-shadow of Mauna Kea, and had almost no wind all day, finally getting to Kona around dusk with a lot of engine time.
I have sailed around Oahu 3 times and strongly suggest that it be done counter-clockwise; the day-winds around Kaena point can prevent any progress in a small sailboat if you try to go clockwise. Have never sailed to Kauai.