For me, I've already accepted my appointment. I don't see a 'need' to scope it out anymore. But if you are still in the decision making process, it probably wouldn't hurt.
Doing the overnight really benefited my daughter and solidified her choice. It also eased her concerns about the academics because she was able to attend classes with her plebe and keeping up in the class/discussions was not a problem.
My cadet used his Easter visit last year to get a pair of boots and low quarters at the PX. The ladies in the shoe department are very helpful in the whole fitting process.