It is not permissible for a Women to travel without a Mahram, whether she is a servant or anything else, because the Prophet-Sallallahu alaihi wasallam- said: A woman may not travel without a Mahram.
As for her presence in the house, she does not require a Mahram, but it is not allowed for a man is not related to her to be alone with her, because the Prophet- Sallallahu alaihi wasallam- said: A man may not be secluded with a women except with a Mahram. And he-Sallallahu alaihi wasallam- said: A man should not be alone with a woman ,for verily Satan makes a third. Narrated by Imam Ahmed with an authentic chain of narrators, on the authority of Umar,may Allah be pleased with him
1.Al-Bukhari no.1863 and Muslim no.1338 2.Al-Bukhari no.5233 and Muslim no.1341 3.At-Tirmithi no.2165 and Ahmed1/18