Moving to Boston

Hi there,
we are moving soon to Boston.
We have been doing our research and finally come up with the conclusion that we would love to be by the beach or very very near by. Work location is around Boston South Station. Thats why we keep looking for places to live south of Boston, like Quincy. Anyone can tell me if this make any sense? How far is commuting really? Is it feasable or it will just adds up to the working hours incredibly? Is it suitable for a family with 3 very small children? How are the neighborhoods there?
Thanks in advance for any help in understanding this great place which is Boston.
Kind regards
Rosalie