In Into the Wild by Jon Krakauer, is Chris McCandless characterized as an individual who expresses his opinions freely? Krakauer writes, "Like Chris, Carine is energetic and self assured, a high achiever, quick to state an opinion." Then another passage states "If something bothered him, he wouldn't come right out and say it. He'd keep it to himself, harboring his resentment, letting the bad feelings build and build." He was a part of Emory's Newspaper and stated his opinions freely there; however, I am still confused about Chris' characterization. What other examples are there?
You have given a perfect example of how either idea can be proved! It always amazes my students to find out that, using clues from the text, you can prove that McCandless was either prone to state his opinions freely or prove that McCandless was not prone to state his opinions freely. Chris McCandless is a complex character, and your question proves the point.
First, let's look at the specific evidence that you have already stated, and see which aspect of the character is exemplified. First, you mention some direct characterization that uses exact wording: "quick to state his opinion." The irony here is that the description is about Carine and not Chris. This is truly a piece of evidence for the one side. Another piece of evidence on that side is the indirect characterization that Chris writes for the newspaper and shares his opinions that way. You could provide numerous examples of specific articles, if you can find them.
The opposite side is represented by the longest quotation you provide. In fact, you could break that quotation apart and uses it as a FEW different supports if you want. For example, Chris "wouldn't come right out and say [his opinion]" and "He'd keep [his opinions] to himself," and he'd let "the bad feelings build and build." Three supports right there!
Now let's explore some other ideas. You could find some more supports for Chris not freely sharing his opinions by fleeing the family instead of dealing with the tension between him and his father. A support with a bit less strength could be how the reader feels distance from the character. For example, Chris always refers to himself in the third person. This lends itself to not sharing opinions freely.
In conclusion, I would say that the number of pieces of evidence that show Chris being not willing to share his opinions freely outweigh the other side. Therefore, as a student, I would probably choose the former argument there are plenty of examples above that can be proved in an essay on this topic.