I checked out this book from the library last fall, and a few months later grabbed the newest edition of it for my very own. I used a similar book when we visited Kauai - they're great for pointing out the lesser-known, often cheaper, but still neat things to see.
[I'm considering requesting their book on Oahu as well, even though the couple of days we'll be on Oahu are nearly completely planned already. I might come across something super cool that we've never seen or tried before.]
Somewhere in there I started to feel anxious that we're not going to have enough days on the Big Island to see EVERYTHING...and it made me wonder if this amount of research - which has become fairly standard for any family vacations we plan - is average or sort of over the top.
This time, I'm most concerned with sharing my research with my immediate family so we can skinny things down to what is most important to us. After that, we can throw it out there to our other travel companions. It's the Big Island though - volcanoes, astronomy, Southern-most point of the U.S. - and it's BIG (duh), which means more travel time to see what we want to see.
I don't plan quite this much when it's Rob and I going - mostly I try to find good food when it's just us.
Is that amount of research over the top? Do you like to plan, or just wing it?