I just shipped a vehicle from Tacoma port to Maui last month. It was around $1750 and overall went well. Yeah, their are A LOT of rules and some seem ridiculous but I kind of understand it from their point of view. They don't want the added weight (that they'd have no way of calculating) or the responsibility.

I can't really see shipping as an alternative since timing would be really tough. They don't give specific timelines at all. Everything is "within a few weeks".

Aside from those things, shipping a vehicle to the islands is a great idea IMO. There's the sales tax thing and then just the cost of vehicles there. Every vehicle has the shipping cost already built-in. Also, any older used car is covered in rust. I shipped a 12 year old Honda Odyssey minivan that I could have sold for about $6,000 on the mainland. For $7500-$8000 on Maui I could only find them full of rust, with twice the miles and generally beat to hell.