The Kona Coast resort on the Big Island is not difficult to trade into. Start 14 months or more ahead, and put in some other choices as well. Chances are that you'll be offered a trade at Kona Coast before you're offered trades to other resorts.
We're traveling there next spring and I plan to post a report. What I know so far is that the resort is well-reviewed, but that one must cross a golf course to get to the beach. Since Hawaii isn't the best island for beaching anyway (we're going for ranches and volcanoes) that might not matter to you.