How do er reconcile this Pasuk, which gives the space around the town as one thousand Amos, with the next Pasuk, which gives it as two?
Rashi, Ramban (citing Sotah, 22b) and Rashbam: The inner thousand Amos are Migrash, the outer thousand, fields and vineyards.
Ramban #2: Given that the town itself measured one thousand Amos square, they first left one thousand Amos by five hundred on each side - corresponding to the town itself, and then added to that - filling in the corners so that the Migrash extended beyond the town - making a total of two thousand Amos square with the town in the middle. 1
See Ramban who elaborates.