I found the answer to my question, so I'll share it here in case anyone else is curious. According to my U.S. history professor, these are some of the reasons why western states were the first to allow women to vote:

1. The west had a relatively small female population in the 19th century, so men weren't afraid of the impact of women voting because there were too few of them to make much of a difference.
2. The populist and temperance movements, which were both very strong in the west, endorsed women's suffrage.
3. Western states could entice women to move west with the promise of suffrage.
4. Vested interests who might oppose women's rights (I'm not sure what specific groups my prof was talking about here) were weaker in the west than in the east because they were established more recently.

I wish these answers were less vague, but this is pretty much all the information I could find to answer my question.

This is a very interesting question. I learned a lot about this when I took Colorado history. It basically boils fown to the west being so wild. Both men and women put up with a lot of hardships trying to survive without the luxuries of the cities in the east. Women played a much larger role in family/town/village politics and were expected to do a lot of ''man's'' work. This led women to being a bit rougher around the edges than their Eastern counterparts but much more assertive in getting what they want and much more valuable in doing more than just ''woman's'' work.

Edit: To sum this all up, even if certain men were against women voting, there wasnt much they could do about it because of their value in survival.