The only funny part I thought the trailer spoiled was the car falling into the (very) shallow river/stream. Other than that I was greatly surprised by how funny it was!
I agree, I really wanted to see this movie after seeing both green and redband traikers and it felt like they put all the funny scenes in a context where they were only half as funny as they were in the film. By the time I watched it, I felt it was given away. Part of the movie was a Napolean Dynamite-esque charm they seems best appreciated going in without knowing what to expect.
...And remember my friend, future events such as these will affect you in the future...