Try selecting the object, then zoom to selection. You can then zoom out at, say, 50%, and you should see the ball-park -- so to speak. Also, don't forget to use the hand tool to move around the scene. As bluetone stated, activate the Production Frame, you will get lost without it -- relative to rendering.

You can also directly size the Production Frame in the Assembly Room by dragging the corners (will proportionally expand if "Keep Proportional" is selected in the Render room); move the entire frame by selecting the center frame point and moving. Select the camera before doing this.