I have a couple of questions about leave/liberty. I know liberty is extremely limited especially during 4/c year, but does anyone have more info on that and info on liberty the other three years?
Weekend liberty increases as you advance. In your 4/c year you will have military obligations on Saturday morning, you will probably get liberty at noon, expiring at 2200. Then you will get all day Sunday liberty, expiring at 1800. If you leave the academy, you will remain in uniform at all times within (I think) 100 miles.
Compare that with what the 1/c cadets get - their parking lot empties on Friday afternoon and doesn't fill up again until Sunday night.
When we get overnight liberty for certain holidays, can we sleep off base or go away from Academy grounds?
That is the definition of overnight liberty.
On some holiday weekends (i.e Labor Day) you can leave on Friday afternoon and you don't have to be back until Monday evening. On Parent's Weekend, you will be able to stay with your parents overnight Friday at their hotel, but you'll have to be back on Saturday morning at 8AM, then you'll be released again after the football game starts and you won't have to be back until Sunday evening.
Leave is different - for Thanksgiving, Christmas, and Spring leave you can leave the academy after your Last Military Obligation (LMO). Some 4/c will have duty and will not always be able to leave when their shipmates leave, so don't make your plans too far in advance until you know your duty schedule.