SFC Craig. When I worked at Little Rock AFB - we had the Reserve there working in the Base Weather Station. One civilian forecaster was pulling weekend duty when he said that his observers were better than active duty. Except for me he said I was the best of them all.
I say this because you mentioned trainability and to some extent I agree because we had enlisted guys with Masters degrees in Physics and such. Many were resistant to be a forecaster because the observing job was easy outside of bad weather.
MSG(P) Matthew Q.: The avenue depends on the student, their qualifications, and their goals. Be careful not to judge the Academies as better than ROTC, etc. They are just different. Each program produces a different kind of leader
First, the academy: Besides the qualifications; the student must want to spend a lifetime of service to the nation and want more than anything else in the world to go to the academy. Otherwise, they just won't be able to make it through. Desire is the essential element. Well rounded and national level leadership, academic, and physical skills are next. However, without the burning desire none of the skills will matter.
Second: ROTC: Basically, the student will need the same skills and desire for a life of service to the nation. ROTC is less rigorous on a daily basis so the desire for service the student needs to succeed is far less intense. The training is excellent and though different than the academy. It provides a junior officer every bit as good if not better than many academy officers. It is also a good avenue for students who don't meet academy academic standards or who can't get an academy appointment to still become an officer. CAUTION: Some ROTC programs are every bit as rigorous as the academy, and the "desire" factor is a greater concern if the student is to succeed. For example, the Citadel.
Finally, I would recommend that the student sit down with a few field grade officers (no slight intended to the company grades out there) and discuss what he or she would like to do in the military and why. Field grades know all the ropes and have the experience to point a young person to the best avenue. They can also write the best recommendations and have contacts at school admissions.