It may only be entered through a magical portal set between two Oaks and can only be left through a similar portal between two Apple trees. Although she may not leave the Vale without being subjected to the attention of Greater Demons, her knowledge of the world is still great.
It is said that she once resided on Titan "when the world was young". She herself has spoken of the fun she had at that time and mentions that one of her companions was the Juja. It appears, therefore, that she was a sorcerer during the Godtime. Thus, she was a Human using magic before the First Battle. This would have been aided by the gods no doubt because at that time they wandered the lands of Titan also.
It is known that the Juja left the world "when the world became Evil" and it is thought that this refers to the time immediately after the First Battle. It seems that Vashti retreated to her magical plane perhaps at the same time. This meant that she escaped the effects of Time. This would explain her apparent immortality and great age. It is not certain how many such ancient users of magic fled the world after Time was released. What appears to be true, however, is that the price for fleeing the world to escape the effects of Time is a huge constraint on ease of movement between Planes. Although safe in their own planes, these immortals face immediate peril if they try to leave. Adventurers have visited both the Juja and Vashti on noble quests to seek their aid.