I'm a current senior here at Gustavus. Lemme give you the rundown of the freshman dorms:
Each room in Sohre and Pitman have a sink and they are closer to the academic buildings but farther from the campus center (so like the cafeteria). There is a social scene but it isn't as big as co-ed (Norelius). A lot of my friends I made when living in Sohre. But Co-ed is the biggest dorm so the social scene is usually a lot bigger, but it is different with each person.
The rooms in Co-ed I think are less nice than in Sohre or Pitman plus they don't have a sink. But it is closer to the Campus center. All the dorms have kitchens in the basement. Also for Co-ed, the parking is a pain because that one parking lot is there for really five dorms (Norelius, Gibbs, Uhler, North and Sorenson).
Hope that helps a little