Completely agree. The challenge is that many high schools have cut art programs from the curriculum. I don’t remember exactly but I think it was UVA that said they don’t accept portfolio’s because they understand this situation and don’t want to restrict the applicants that might not have had that exposure.
My son took an online course through Syracuse - sounds similar to yours through Roger Williams except they didn’t visit other schools. He definitely ended up with a couple of pieces to be able to include in his portfolio (2-4?) but caution to the parents/students that think a summer course like that is going to get them their whole portfolio - it won’t.
Given the commitment that admissions to a B.Arch program entails we wanted to use that summer program to gauge our sons commitment to the career path. It was an extra expense but the credit transferred into the chosen school.