We went to Kauai in January 2014 with Kelley's parents, Debbie & George, who had never been to Hawaii before. We stayed only about 5 days, and they stayed an extra 4 days after we left.
We stayed at the Outrigger Kiahuna Plantation in Poipu. While there, we went to a luau at the Grant Hyatt in Poipu, went on a snorkeling cruise up the Na'Pali Coast, visited the Hindu temple on the island, saw a couple waterfalls, went for a hike, and were proper beach bums on a couple of days. It was a really great trip, and it was a lot of fun showing my in-laws around a place we had been to for the third time in three years.