Hookup running board lights?

[jamesewells]

I am installing Westin running boards on my 2003 SR5 and was wondering about the easiest way to hook up the lights? I can see a rubber grommet that looks like it's under the sill plate and might provide interior access. Do the sills just pop off? Is there a way to hook up each side separately or should I run a wire across? I know I can get power where I tapped into the ECU for the map light mod but I was wondering if there is an easier way?
Thanks for the help.