Reference: al-Muqarrab li-Ahkaam al-Janaa.iz – Question 138, Page 120
Question: A woman’s husband has died and she has no children from this marriage. Additionally, there is no-one from her relatives in the land [where she resided with her] husband, so is it permissible for her to travel from the land [where she resided with her] husband to the land where her legal guardian is in order to spend the period of mourning there or not?
Response: If she feared for her safety or violation of her honour and there is no-one with her to protect her, then it is permissible for the wife to travel to the home of her legal guardian or to anywhere else where she will be safe and protected to complete the rest of her period of mourning. If, however, she was safe from harm and simply wanted to be close by to her family, then it is not permissible for her to travel, rather, she is required to remain where she is until she has completed her period of mourning. She may then travel with her mahram (male who is prohibited to her for marriage) to wherever she wants.
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet Muhammad (sal-Allaahu `alayhi wa sallam) and his family and his companions.