Well i am glad you asked, farmers having dreams means that they have optional reasons of farming techniques...they especially like dreams about pandas eating ice cream:)
Yes, college is good for farmers. College helps the farmer learn more about agriculture and it also may teach them how to do things where they might work out better than what they were trying to do.
i don't think there is a cheat for it but if your a high level past 13 plant the one with the least days hour or minutes do the math in you head see which does the most.