I’m a high school senior and I want to visit UC Merced but I’m not sure if it is necessary to go on a campus tour or is it okay to just go on the campus and take my own little tour.
Take an official tour. They are usually led by current students who are a wealth of information about the UCM experience. They can also fill you in on the growth plans and answer questions you are likely to have (weather, cars, security, parties, clubs, etc) - from the student’s perspective.
You won’t get the same feel from simply walking the campus.
I’d also encourage you grab a meal on campus - stop students and ask them how they like it. What do they love and what do they hate. Current student know just what you are going through and will give you the straight scoop.