This is a map taken from www.archinomy.com of what Ferozabad ( Though the word Kushk eis used for a palace since here we are talking of an entire city that word has not been used by contemporary historians) would have looked like in its heydays.
It was used as a prototype by later kings.
Shams Siraj Afif in his Tarikh e Firoz Shahi gives a description of Sultan Firoz Shah Tughlaq sitting in state: he uses the word palaces for the area where he would hold his darbar. First of all we have to keep in mind that t terminology differs with age. What he termed as Palace and Quadrangle were probably referred to as as Dewan e Aam and Dewan e Khas by later rulers and historians. Reading of history is also a matter of interpreting it correctly and reading between the lines keeping in mind the time in which and for which it was written.
“There were three palaces in which Sultán Fíroz used to sit publicly in state. One was the Mahal-í sahan-i gilín* (the palace of the clayey quadrangle). It was also called the Mahal-i dikh, i.e., the Mahal-i angúr, or Palace of Grapes. The second was called Mahal-i chhaja-i* chobín. The third was the Mahal-i bár-i ‘ámm, or Palace of the Public Court, and it was also called Sahn-i miyánagí, the central quadrangle. The first palace was appropriated to the reception of the kháns, maliks, amírs, officials and distinguished literary men. The Mahal-i chhaja chobín was for the reception of the principal personal attendants. The palace of the Sahn-i miyánagí was used for general receptions.”
These would be where the map shows the Dewan e Aam and Dewan e Khas. There is no way that the Khans, Amirs,Maliks, distinguished men etc could have been allowed to come near the area where the Sultan’s residential quarters and harem was.
The residential palaces were on the river front and would have been cordoned off from the general area and guarded by Khwajasaras or eunuchs.