Where do I go now since Soundtrack keeps crashing on my Mac Mini?

Have you tried trashing your preferences? That's the usual first step when the Pro apps begin to act unexpectedly.

You can download Preference Manager from Digital Rebellion (free) and it will do the heavy lifting for you:

http://www.digitalrebellion.com/prefman/

Your preferences will be reset to default the next time you launch Soundtrack Pro.

MtD

Soundtrack hasn't worked properly since Mac OS X 10.9

Is you are looking for alternate software, Avid is going to make a version of ProTools that will be free:

http://apps.avid.com/ProToolsFirst/

and I like Audition, which is part of Adobe CC.

MtD

Info here:

http://www.digitalrebellion.com/blog/posts/how_to_trash_preferences.html

MtD

Are you looking in your user library, not the system library. On newer versions of OS X it is hidden. Here are a variety of ways to access it: http://osxdaily.com/2011/07/22/access-user-library-folder-in-os-x-lion/

Or you could just use Preference Manager (linked above) and it will take care of that for you.