I always recommend the Kauai Revealed Guidebook for first time or seasoned Kauai visitors. This book can be used for yearly visits and the information inside will keep you busy seeing and visiting places on Kauai even some of the locals don't know about. You can get an ebook version and you can also get an app that could be used while you are traveling. We have both the ebook version and the hard copy version. I included a link below so you can check it out for yourself.