I've been to the various islands of Hawaii several times and simply would not bother bringing an RV there. We love the islands, but none of them are big enough to spend more than a few hours driving around it. Nor are there facilities for them or places to park.
And not only would you have to ship t there, you also would have to ship it between islands to see more than just Oahu. And if you went, you surely would not want to miss Kauai, Maui and the Big Island (Hawaii) as well.
By all means go, but leave the RV at home. Rent a suite or a cottage and spend some time touring on one island, then hop to the next using the excellent air system, and repeat the process on the next island. You will have a ball day tripping on each of them.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL