To stop people from getting on the stage, have one or more people stand in the way.
When you go on the monkey bars, it says left and right but do left twice instead and then you can go straight to the finishing line.
If you want the other person to get out - wave your hand over someone elses "Shake & Stop" Screen. and they will get out, not you.
To move faster, all you have to do is make as much movement as possible in the camera. I usually do Jumping-Jacks or wave my arms around to get more movement.