Unhappy at elite college... Should I transfer to an "inferior" local school?

The students that party like that are the ones with the worst grades.

This statement is ridiculous. It completely depends on the individual. Some people have a “work hard, party hard” lifestyle and do very very well in college.

As to your situation go back with your best foot forward. When the time comes put in a transfer application and then you will have the option at a later date. Try not to think about it too much right now.