I agree with the above. Multi-city booking is the easist way to do it. We regularly fly Alaska Airlines to one island, and fly them back from another. The difference for me is the interisland leg. We use Hawaiian Airlines for that.
The Alaska Visa card is a great way to get lower-cost airfare. I use my $99 companion fare voucher to offset the ticket cost. We can get two First Class tickets for the price of one plus $99, which averages out to around the same cost as two coach seats.
Hawaiian Airlines also has a Visa card that currently gives (I think) 35000 miles on signup. I like to use those miles for the interisland part of my trips. It makes it easy to book a one-way hop for several people without spending a lot. Their card also gives one-time discounts for two coach seats from the Mainland to Hawaii and back. That may be something to look into.
Dave