I would assume they would encourage visits before informing students even if that isn’t likely letter. That is how many schools assess interest. Most schools send out material suggesting visits prior to accepting students. Then they designate specific dates or weekends after the acceptance which they Call “Accepted students weekend” or “College Preview Weekend”. From what is posted here, it does not suggest a specific weekend like “I hope once you are accepted you come for College Pre-view Weekend on March 14th” for example. It is just a general suggestion to visit the campus and keep RPI in your thoughts. The letter does sound positive but it is hard to know if that is a likely letter or is just being sent out but a regional admissions rep or what.