Is it permissible for a woman to travel for study or work without a mahram if transportation is via public means and accommodation is in female-only housing?

A woman is not permitted to travel a distance that necessitates travel except with a mahram. Her travel with female students does not suffice in place of a mahram. However, residency does not stipulate his presence. The questioner is advised to marry a righteous man with whom she can reside in her city of work, or that her current husband, if she is married, move to her, to facilitate matters of going to work and studying without the need for a mahram.