According to the story, following Aisha's suggestion, it seems they made use of a caravan of merchants to move around at night as well.
Just, such caravans of merchants fundamentally don't accept outsiders.
It seems in exchange for allowing Aisha to ride along, they offered Ruijerd to be used as an escort.
With Ruijerd and Ginger acting as escorts.
The pay for that was allowing the load of the two young girls.
It was a good purchase, is what it means.
Although, it seems those negotiations weren't all that simple.