Is it possible to use WPMU plugins without the WPMU Dashboard, or is that a requirement? In my scenario I have some sites I'd rather not install it on.
I've downloaded a standalone copy of WP Smush Pro. I installed the plugin but when I activate the pro features are not available. I have an API key from my WPMU control panel, but I don't see anywhere within the Smush Pro settings to define an API key.
In contrast, if I install the WPMU Dashboard plugin on my test install, it sets an API key in my wp_options automatically:
Even after the Dashboard plugin is removed it seems the WP Smush Pro continues to work (with pro version)