I am not very familiar with Union College, but I did go to a similar sized school (Clarkson), and now live less than 2 miles from the college. In my case, our college charged a lot of money to live on campus and there were only certain housing options that were nicer than off campus options. Clarkson posted the exact amount you would pay to live on campus, depending on where you lived on campus, and it was very easy for property owners to look at those numbers and price accordingly. It's possible that you can find the room and board rates on Union's website. Any college that makes money will always push students to stay on campus as they will make money off of room and board and are likely to get more money off of meal plans etc.
The area is unique because there are very nice well kept properties as well as run down rentals. Patrick is right and almost all of the homes are very old large houses with many converted to multifamily homes. I have been keeping a close eye on rentals in the area and there have been a few that popped up specifically stating they only rent to college students (zillow). You may be able to contact the person who listed the rental and get some good information on the student rental market.
Lastly, since the homes are so old, I would really recommend you get a good look at the inner workings of the house. How is the plumbing and electrical? A lot of these homes have slate roofs that are very old and can be expensive to work on. The home I just purchased in the area was supposed to have all updated electrical and plumbing. It wasn't until I started getting behind the walls that I realized there is still very old electrical and plumbing in use.