Brown University states on its website (see below) that visiting campus will not improve the chances of acceptance into the college. A visit to the campus may provide you with the information you need to make an informed college choice, but it will not impact acceptance.
"Does Brown show a preference in the admission process for students who have demonstrated interest by visiting, calling and emailing?
Not at all. Contacting the Admission Office is neither a requirement nor an advantage in our admission process. We offer campus tours and information sessions to provide you with the information you need to make an informed college choice, not evaluate you. And we welcome calls and emails for the same reason. Please do not feel compelled to contact us to demonstrate your interest in Brown; we know by the very fact of you applying that you are seriously interested in Brown. The number of times you call or email us will not have an impact on your admission decision." https://www.brown.edu/admission/undergraduate/content/does-brown-show-preference-admission-process-students-who-have-demonstrated-interest