What are some highly recommended Hawaii vacation packages?

My parent's 25 anniversary was last year and unfortunately me and my 3 sisters were unable to do anything due to financial standing and school etc. But now, I want to make it up for them by buying them an all inclusive trip to Hawaii (we never travel anywhere besides Florida so this is HUGE for our family). My parents aren't big on crowds and my mom loves seeing natural beauties, not to mention she can name just about any plant in its common and latin names. So I want the trip to be relaxing, not too many crowds, and no worries. That's why I wanted all inclusive, so that when they get there they don't have to worry about anything, and they already have a bunch of things they can choose to do. The other stipulation would be that my dad has a seasonal job, so it'd be even better if I could present the with a package, but they actually choose WHEN they go. (It's not necessary but I thought that'd be nice for them to choose when). Since I'm really new at trip planning, I was hoping someone could recommend a website or agency to use. Thanks!