I don't know about schools. But if you live near a club or facility that gives sailing lessons, take a couple. If that doesn't get you far enough along, then probably a school is what you are looking for.
I teach part-time giving weekend lessons to locals, or others who are visiting New Orleans. A couple of basic keelboat lessons in a decent, responsive boat may do the trick for some learners, especially if you have a way to get out with friends on their boats too (easy here, just hang on the docks on Wednesday race nights for a ride).
Power Squadrons or Coast Guard Auxiliary classes can teach you the chart and piloting work, and most of the practical and regulatory dos and don'ts. Then it's a matter of how to plan for a cruise. Get invited on a couple of short coastal trips or deliveries if you have a winning personality and know the basics. Or crew on some coastal/offshore races.
I think once you can handle a boat in a breeze on all points of sail, run an engine, and get from A to B on a chart with a compass and a GPS,, then you just need to add some "camping writ large, or writ wet" skills to your repertoire, meaning provisioning and weather awareness.
Now what I think I've just described is what a school will do for you all at once. I learned it basically as described in the "non-school" method back in the '60s. Did some racing, some deliveries, and picked up a captain's license along the way.
Now I get to teach. Is this a great country, or what? ;-)
But what I'm getting at is that it's easy to learn to sail if you live where sailing is going on, and you are determined, personable, and helpful.
But if you live where boats are not, or don't want to cobble together a do-it-yourself program over time, then maybe the resident schools are the way to go. Most who have gone to them speak highly of the experience.
Different horses for different courses, I guess..