Well the mandatory hijab is to cover all of her hair and  loose clothing from the neck down.

The clothing can be in any colour and design

providing that it is not intended to attract attention (or flaunt oneself)

 It can be well made and expensive according to an authentic hadith.

However, it should not be bought for the sake of buying a name and in the name of extravagance (as a muslim is responsible for the money they spend)

Part of the hijab is that she cannot be alone in a room with males.

however, as I have stated before I don't think this needs to be the case when conducting business and their are ways around this. (i.e. one can find alternatives to sitting in private places with collegues and muslims need to define those places ( in what is reasonable)

and she cannot travel alone with males.

Maryum : Umm Hasan bint Abdullah Alshabrawishi