Welcome to the forum! I've hung out in Redlands - some of my college buddies are from there!
The big island has some all-inclusives you could look into, but in general I think Mexico or other Caribbean locations give you more bang for your buck. If most of your guests are coming from the west coast, you may want to look into West coast mexico - like Cabo, PV, or Zihua/Ixtapa as the flights are usually very reasonable from California.