Overnight well worth the time & expense. Take advantage of it. Advice from cadets who did them is that if you don't like SLE you won't like USMA. But that it's just a glimpse, and you need to see a more accurate picture of cadet life. The only way to get that is the overnight.
Make sure to spend some time with upperclassmen. Ask if needed, Interview the Company Commander or 1SG. Plebes are so heads down doing Plebe things that sometimes they do not share the big picture. Don't opt out of company athletics if offered, etc. This is your chance to see real cadet life, not recruiter, old grad, parent, or similar input. Try to get the point of view from each class, it will be different.
DS felt his overnight gave him an accurate picture of cadet life. No real surprises or disappointments 3.5 years later.
Look past food, quarters, and tales of no TP. Instead, look at the cadets who you will spend time with even if they are a year or two ahead. Learn what they did last summer if Cows or Firsties
Likewise, the parent part of the overnight really opened our eyes, especially relative to USNA overnight experience. Briefings by staff, briefings and tour by firsties, etc.
DS was very impressed with the company commander he met with. Actually, the firstie sought out DS and spent an hour with him. DS left the visit saying "I want to be that guy". Not the position, but the combination of quiet leadership, confidence, and capability.
You are about to pick how you spend your next 9-10 years (at the minimum). Make an informed decision.