Fortunately my son did not play football so he had the fall for baseball
He used a combination of all three, camps, showcases,the few that were there back then, and his travel team.
The key for him was marketing and having his name out there. Getting ranked by Collegiate Baseball as one of the top HS outfielders in the country did not hurt either. (Marketing)
In fact he got his scholarship situation sight unseen due to the fact that coaches who knew him and had seen him recommended him to the school he ended up at, New Mexico State. Keep in mind that he lived in New York so obviously the marketing worked
That was 11 years ago but the process still works and I truly believe that being proactive (marketing)is the key. The huge difference now is that there are more showcases and more real good travel teams. The key is to let the schools know where he is playing.
It now comes down to more choices and I would go with travel teams and showcases for maxiumum exposure. The camps work if the coaches have a specific interest in the player and want the player to be there by specific invitation.
I hope this helps you