Is it permissible for a woman to go on a trip with her brother-in-law and her husband's niece's husband?

It is permissible for a woman to go on a trip if her husband grants her permission, and if there are no forbidden acts involved (such as impermissible singing), and it is not considered a journey unless she is accompanied by one of her mahrams (such as her husband's father). She must also observe Islamic law regarding modesty, covering, and avoiding intermingling with men.