First, let me see that I understand your question clearly. As I see it, you have two questions: The first is a question of understanding the meaning of "Galus." You essentially ask, it is not such a big punishment, especially in the context of the crime. Your second question is: When a family man is Chayav Galus, does his family go with him?

The Maharal in Netzach Yisrael (Perek 1) explains that Galus is an unnatural state of affairs. He says that there are three facets to this: 1) that the members of the nation are disparate; 2) that others rule over them; and 3) that they are not in their natural habitat. It is this third facet that is so important here. The event of being removed from one's native location and being obligated not to return there is a serious punishment. This is deeply rooted in the Creation, as you see that the first murderer was punished with Galus. Perhaps in a modern society we find this difficult to understand (the average American moves 5-6 times between the ages of 18-45). Ha'Gaon Rav Moshe Shapiro zt"l once said that one of his ancestors was born in the same bed that seven previous generations were born in. Quite a difference, no?

As for the second question, I could not find any explicit proofs. Of course, the Torah says "v'Chai" and Chazal taught us that the Arei Miklat must be enabled to give full life support to the Rotze'ach. Perhaps the most extreme example is that if a Talmid goes to Galus, his Rav must go with him. This would seem to indicate that of course one's family may accompany him to the Ir Miklat. However, the Tzafnas Pane'ach says that it may be that this Din is not universal and applies only to Torah. The Radvaz (cited by the Minchas Chinuch at the end of Mitzvah 410) says that a king would not go to Galus because one would have to send all of his subjects with him; the Minchas Chinuch strongly disputes this. So it is logical, but unproven, that one's family may accompany him. Are they required to do so? The Tzafnas Pane'ach says no, a husband does not have to accompany his wife when she is sent to the Ir Miklat. On the other hand, unlike a man to his wife, a woman is obligated to remain with her husband (see Ritva to Kidushin, ver. 2, Daf 29a, DH u'Mai), so it would seem that she would need to accompany him. Once again, I could not find any explicit source to answer this question authoritatively.

Shimon Brodie