have u tried local community college(s)? it'd be a much cheaper alternative to HSS. plus u won't have to move to boston, and boston living expenses are crrrrazy.
UCSD has an Extension program, all you have to do is pay the $800 per course. You can also take Summer courses through the extension (regular university undergrad courses). This may be true for all UC's
Also, San Diego State University also has Open University where you can take any undergrad course.