Hello hetty, and a belated welcome to cruise-chat;
I think a little more information would be helpful in knowing what kind of advice to give you: in particular, what ship are you sailing, which ports are you visiting, and what is the nature of your disability. If it's tendering you are inquiring about, Honolulu and Hilo are two ports where the ship will dock. Nawiliwili has a dock but there is only room for one ship, so we had to tender in when we were there in April. If you are confined to a wheelchair, rest assured that the cruise lines make every effort to accomodate such passengers. And there are plenty of shore excursions available for those with limited mobility.
As I say, give us a little more information and I'm sure you will get more responses.
Have a wonderful cruise.