Simon’s Rock has a very particular vibe. If it suits you. it’s great, but if not, it might not be a great place to be. Did you visit and like it?
Given that you can stay at home and the cost works, UW sounds great. You will have the company of other students your age (I assume this is true, but am less familiar with the workings of the program) but be able to get the academic challenge you want. In your shoes, I would do this because it’s a great opportunity now rather than hold out for a “higher ranked” college experience that might be better but might not.