For the overwhelming majority of schools, the number of AP classes, or even the rigor of the HS curriculum is not a factor in recruiting or acceptance. For the Ivy League and NESCAC both are important - and maybe some schools in the Patriot.
Even at those few schools, once the academic bar is cleared, there is no extra credit for clearing the bar by a wide margin. In other words, being a better student does not mean that the kid can be a lesser player. (Although a coach may only be able to gain admittance for only one "lesser" student.)
Yes, the APs for many are a race to nowhere; for others it's the only way to hold a student's attention (they'd be bored with regular classes). Ironically, in the few schools which essentially require a kid to take the most rigorous classes to gain admission, most don't allow you to cash in your APs for credit (it does allow for placement immediately in more advanced classes); therefore, no lightened class load or even the chance to graduate early.
My S actually took an extremely light HS senior year - he wanted to focus totally on baseball. His big push academically occurred during his soph and junior years.
So, unless a kid is hoping for those few schools (and no athletic money at those schools; heck, most of those schools don't even give merit money), IMO, the student athlete should only take on what he is comfortable doing.
As for ECs, my S had none - just the bare minimum of what the HS required to graduate. His EC was baseball. I do not believe athletes need to be the well-rounded student the regular admits need to be. (My D, a regular admit, ran the "required" insane gauntlet of APs, ECs, science fairs, volunteer work, summer jobs, etc.)