having too many quests at one time...

I find it difficult to do "influence island" , " sim chase" and the collecting crafts at the same time. I always find myself picking one or the other. I end up doing the sim chase cause I can never complete influence island. whenever I'm at the last step I get discouraged cause I can't win them over and I have no idea when to use the chocolate. and has anyone ever won the final prizes on the collecting crafts??