The gift to Panadavas, a dubious one, is treated very differently by the three versions I read. The briefest one is Vachana Bharatha.
Bheeshma and Dhirtarashtra send for Pandavas. Dhritarashtra says: 'Kaunteya, you and your brothers pay attention to what I am about to say. By staying here, there may be fights, let us avoid it. Take half the kingdom and move to Khandavaprastha and be comfortable there. Thus Pandavas proceed to Khandavaprastha.
The place is a dense forest. Pandavas build a city, with a fort reaching the sky, surrounded by a moat as wide as the sea, heavenly multi-storied buildings, gardens with flowering plants and fruit bearing trees, creeper bowers with birds and peacocks, lakes full of lotus with swans and other birds floating in them. Soon the city filled up with vedic scholars, experts in languages, merchants and artisans. Pandavas were happy as the rulers!
That was indeed brief! Kamala's version says: Vyasa appeared and there was a coronation in Hastinapura and Yudhisthira was installed as the king of Khandavaprastha, on an auspicious day chosen by Vyasa. The preparations were lavish.
Once they reach the place, Krishna summoned Indra and tells him to build a city which will be named Indraprastha and says; 'Make it so wonderful and so fertile that its equal will be only your world, the Indraloka'. Indra replies: 'Visvakarma, the divine architect, will take charge of this. It will become the most wonderful place in this entire world'.
Vyasa was there, again, to choose an auspicious day and recite holy incantations at the start of construction of Indraprastha!
She also adds that an enchanted palace was built by Maya, the asura architect, in gratitude for being saved by Arjuna when the forests were being burnt to make way for the city.
The construction workers!