Spoiler
For the side quest Forbidden Legend, you have to enter the ruins of Saarthal for a piece of the amulet. In vanilla, the only way to get the key to Saarthal is to join the College and then all the excavation members show up, including the guy with the key.
So... that being said, would it break anything if I simply added an alternate way into the ruins (such as a container with a key)?