1)
In Divrei ha'Yamim II, 8:5 it says that he built Beis Choron ha'Elyon, and Beis Choron ha'Tachton was a fortified city!
1.
Malbim: He built Beis Choron ha'Tachton twice. It was desolate, and it says here that he built it to be a settled city. Afterwards, he built it and Beis Choron ha'Elyon to be fortified cities; Divrei ha'Yamim discusses this.