Not much of plan beyond vengeance against one man really... the Genesis Device can only be used once. Then he's still facing overwhelming forces intent on hunting him down.
I suppose like the Xindi, the Romulans (so we're told), the Borg... he'd get through to Earth but instead of decimation or assimilation, within a short time, have a nice lush planet to rule over.
Although just the Reliant, wouldn't be enough to protect him from the rest of Starfleet once that's done. He'd need allies.