Hello Caleb and welcome to FT;
A couple of suggestions:
1. read the posts that are available. there is tons of information about each of the islands and all the things to do. then you can come back with specific questions. You are more likely to get help
2. if you share more information such as budget, interests (apart from hiking) - it would help to give you suggestions. 8 nights in Hawaii is plenty of time to see 2-3 islands but that can be pricey.