An extra half hour on from Double Island Point you can get to Rainbow Beach. Visit the Carlo sand blow from the township and the famous rainbow coloured sands along the way. You can also take the road back - it heads into Gympie, then you head back south along the Bruce Highway.
Take the various inland easy 4WD tracks heading to Rainbow Beach via Boreen Point (great pub here) and then through the National Park to Harry's Hut (and beyond).