It also depends when in the day you get there. And even then, it would be impossible for sometome to tell you exactly what you'll encounter.
IF you head there first at park opening (Assuming it wasn't an EMH day) or if you head there first thing during EMH hours, then the wait will probabably be fairly short, or about as short as it gets. An hour later, forget it.
Our family has always done the split thing. If your family has little ones, you might go on RnR while they go to Playhouse Disney or maybe the Beauty and the Beast show. The only thing with splitting up like that is once in ahwile RnR is down, and then you'd be stuck doing nothing waiting for them. It has happened to us. I'd also suggest you get a fastpass. Your family might even be willing to let you get several fastpasses with their tickets so you could go on it more than once.