I attended Tzu Chi last year and few of my classmates stayed in the dorms; these were all in their early 20s and from other Asian countries.
There are four people to each room, no air conditioning, and officially cooking and meat are not allowed, but the students I knew snuck in meat and cooked instant noodles and dishes from their home countries. The cafeteria is strictly vegetarian. Teachers, staff, and students in the Chinese Language Dept. will often bring snacks to share, but remember to only bring non-meat items. The students I spoke with did not like the curfew, but they were used to similar situations in their home countries.
The rest of us, who were older and/or came from other countries, preferred the freedom of living off campus. Some lived close enough to school to walk, others had bicycles, and some of us had scooters. I believe the dorms are 3,000nt per month, while off campus places run about twice that amount for the cheapest places (and you’ll usually need to pay a two-month deposit, plus pay for utilities, etc.). Check out http://www.591.com.tw/ for rentals, which can easily be translated into English with Google translate.
I’m not in Hualien anymore, but I still keep in touch with some friends there. Contact me if you’d like them to give you some pointers about finding a place there.