having read the first book and a bit of the second one, I realised how spoiled we've been with the way Head British TERF presented the world. every bit of Hogwarts has been vividly described with great detail, while here? I can't remember the single detail about the summer camp thingy, other than "there were some houses".
Most of Percy Jackson took place outside of Camp Half Blood, unlike Harry Potter, which takes place mostly at Hogwarts, so it's not surprising that Hogwarts got more detail. Also, Camp Half Blood had like 50 people in it unlike Hogwarts that had hundreds, so naturally it'd be less noteworthy.
Edit: I just checked and only 6 of 22 chapters of The Lighting Thief take place at CHB.