There's no "Least Strict" when it comes to the academies. This is why so many doolies, plebes, etc. QUIT. Matter of fact, I'd say the entire 1st year is a PITA. It does get a little less strict once you're no longer a Doolie or Plebe, but that first year for sure is strict for everyone.
Nothing against those who visit the academies, go to summer seminar, etc. but that isn't designed to give you any sense of what it's REALLY LIKE. It's simply "Marketing" and a chance for you to put SOME realism to until then was something you only imagined. That's like the misunderstanding many JrROTC and CAP members in high school have; THINKING that because they are member of JrROTC or CAP, they "KNOW" what the military is about and they are "READY" for it.
Put it this way. I had an applicant who received an appointment to the air force academy. He was in JROTC. He was the commander of the JROTC unit at the high school. Been doing it all 4 years of high school. Felt very confident with being prepared for the academy......... He DROPPED OUT half way through basic training.
Sorry if I can't give you an answer you're looking for. Then again; not sure WHY you are asking such a question. Are you looking for the "EASIER" way out? Or the opposite and looking for the more difficult. NEITHER should play into your decision on which academy to apply to. You should know WHY you want to apply to one of the academies. There are some that apply to ALL of the academies; including merchant marines and coast guard. Some do that because they are looking at the "FREE" college education. Some truly do simply want to serve and don't care what branch they serve in. MOST applicants know what they want. They know where their skills and demeanor will fit better in; and they only apply to those academies. My son was like that. He only applied to the air force academy. If he wasn't accepted, he'd go for Air Force ROTC. If that didn't work out, he'd attend college on his own and apply for OTS when he graduated. In other words, he only wanted the air force. He never applied to anything else.
Not saying you should or shouldn't apply to only one. Simply saying, you need to know WHY you want to be an officer in the military. Then, determine the type of officer you want to be. Then, choose the academy(ies) that will help you be that type of officer you're wanting to be.
But the first year at the academy; ALL of them are strict. It really sucks at times. Some quit and some put up with it. ALL of them get better the 2-4th years. But that first year; especially at basic training, they will be in your face and tearing you down. That's the purpose. What you experience when you visited; was simply "MARKETING". Just like any college trying to recruit you. If you visited during september when school was back in session, you probably saw a typical academic day. All the academies have 3 MODES. 1) Academic mode; 2) Military mode; and 3) Brain dead mode. After breakfast during the week, it's mainly academic mode. Same as most universities. If that's what you saw, it's similar at all academies. But when not in class, it's military mode or brain dead mode. (Brain dead mode is what little down time you have when not doing military stuff or studying.)