From what I know, most of Preppies receive appointment to come to the Academy unless they're in legal conflict or failing down at the P. If this is your situation and you know that you're not getting a spot at the Academy then I would ask myself if military life is something that you want to pursue. Are you willing to follow the rules and deal with people telling you what to do? Are you willing to sacrifice personal gain/pleasure? If not then I wouldn't suggest pursuing the AFRTOC. I did little bit of ROTC while I was at UCONN. It is definitely much more relaxing than the Academy, but they still have the same expectations as they do at the Academy. If you didn't earn your spot at the Academy and you are willing to pursue the military life, then I highly suggest AFROTC. From experience, I think civilian universities grade more generously. They don't emphasize too much on core classes like the Academy which allows you to pursue your interest and your degree. Grade inflation in civilian institutions are very helpful if you want a good GPA.
Something you should keep in mind is that you will not get any of the experiences that you get at the Academy without paying a lot of money. Cadets have tremendous opportunities and you'll be able to experience most of that if you work hard here. It's up to you to take the challenge. Stay positive because this place can wear you out. SURROUND YOURSELF WITH PEOPLE WHO CAN BENEFIT YOU AND ARE WILLING TO MAKE BETTER.