I'm studying in a dorm, where there's no WiFi access, but there are LAN ports available. Since i have a lot of WiFi devices (MBP, iPhone and iPad) i was planning to take a wireless router and set it up there. BUT i've read about the modem having to restart for the router to work properly. This will not be possible as the Modem is not accessibe to the students, and like i said, we only get ethernet/LAN ports in our rooms, and already connected. Is there any way i can set it up?
Not sure what you are looking at related to a modem. Likely there is no modem in the path only a switch or router. You should be able to connect a router that will to the network look like a end device such as a PC and it can then extend to your other devices via wireless.
In general many places have rules that say you should not do this. If you were to install it with no security you would open their network to attack. Now they may have technical measures in place to prevent it or at least make it hard on your to put a router in. I would check if its ok to do what you want and if it is they can likely give you recommendations on how to set it up.