Joseph Smith was not a "drunk" per sé, although, yes he did drink alcohol, smoke, and chew tobbacco, HOWEVER that was before the revelation of the Word of Wisdom. After that was revealed, he quit. Also, there have been accounts written BEFORE the revelation of the Word of Wisdom that Emma tried to get him to quit, though he didn't. Once again, you must understand that this was a cultural custom at that time. Tobbacco and Alcohol were widely used by many people. Like I have said how things change over the years, alcohol and tobbacco have changed in the way they are injested into the body.
The corn-fields... yes they exist. There are also wheat-fields, and fields of other grains. They are owned by the church's welfare system and that food that is harvested is sold as grains in mass, and are part of the whole idea have having provisions that will last a long time should your family need them in times of dissaster. Jesus is not going to land in a corn-field in a UFO like some alien, as you seem to have picked up that little factoid. Your seminary teacher had what is called a personal opinion, or a mistake.
Just out of curiosity, do you believe that the movie "The Godmakers" is an amazing documentary?
I have never heard of Jesus coming back in a corn-field. That just ain't going to happen.
As your post seems to indicate, you were baptized at a fairly early age, learned the customs of the church, yet didn't learn of how things came about, or to say, the basis of those customs, and then were easily swayed by either misunderstaing teachings or hearing non-doctrinal teachings, and have solidified your ideas in stone, possibly due to hostility towards the church. Just a guess.
H-D 