How do I get the camera to follow my text being revealed with Opacity range selector?

There is nothing in the screenshot that I see that requires anything but a soft edge track matte and a simple position animation. 

When you are creating a rolling move like this it is critically important that you pick the right speed for the movement of the text so you avoid judder. What is Judder? When something with hard edges and a lot of detail or contrast moves across the screen it is very easy to create a stroboscopic effect on the motion based on the shutter speed. The edges of the text also should be moving precisely an even number of pixels per frame. If they don't the aliasing on the top and bottom edge of the text will change with every frame making the height of the text appear to be constantly changing and flickering.  Creating a simple line by line fade in and fade out is incredibly easy with a track matte, and a very simple expression can move a layer at precisely the right speed no matter how big the text area is. 

Here's how I would approach the problem.

1. Create a new text layer and draw a container for the text by clicking and dragging the text tool in the Composition Panel
2. Paste in your text
3. After you have added the text you can double click the text layer to select all text then carefully grab the bottom of the text box and expand it to make sure that all of the text is included
   
    
   • An alternate method and one that will give you a lot more control on typography would be to create your paragraphs of text in an Illustrator document, format the text exactly the way you want it and then import the AI file
4. Add this expression to the text layer's position property:
   spd = 4; // pixel per frame
   fr = time/thisComp.frameDuration;
   x = value[0];
   y = fr * spd;
   [x, value[1] - y]
5. On the first frame of the text layer drag the layer into its starting position
6. Verify that the speed is OK. 4 pixels per frame is a good readable speed for a text roll in an HD comp
7. Add a solid above the text layer
8. Select the Rectangle tool (q) and draw a mask around the center of the solid approximately where you want the visible text to appear
9. Press "f" to reveal the mask feather and feather only in y until the mask has a soft top and bottom edge
   
10. The last step is to set the solid layer (track matte) to an alpha track matte for the text layer and fine-tune the size of the mask and the feathering
11. If you have a lot of these to do save both the solid with the Mask and the expression for Position as animation presets

That's all there is to it. You are making this way too difficult.

There is another approach just using text animators to control the position and opacity of the text, but it is way too hard to solve judder problems using text animators and the expression is a lot more complex. 

One other suggestion. The screenshot shows fairly thin black text against a white background. H.264 compression is going to have a hard time with that contrast range. I suggest that you make the white have a brightness of no more than 94% and that you set the black text to a brightness of no less than 10%. H.264 8Bit MPEG compression is going to have a lot more room to handle the aliasing of the edges of the text if you don't crush the blacks and blow out the whites. Nobody will notice that the white isn't 100% white and your text will be much easier to read in the final movie. Here's the setup for Black text at 12% brightness which I think is a really good choice.

I hope this helps. The trick to being a really good motion graphics artist is learning how to simplify.

You might also want to take a look at these two articles that Todd posted a long time ago. The one on Judder was written by me. 

FAQ: Why does horizontal motion stutter (judder)

The new forum format didn't treat the article very well but if you push in on your browser you should be able to read it.

To give you an exact solution I would need to see your timeline with the modified properties of the layers involved revealed. If I was setting up this kind of a project I would reference sourceRectAtTime for the text layer so could derive the size of the paragraph. This would give me the width of the paragraph. Then I would reference the animated range selector and convert the percentage into a percentage of the size of the text layer,  then tie that whole thing to the point of interest or the position of a camera. 

The exact workflow would depend on a lot of things including how the camera moves. Just a vertical movement as each line is revealed would be the easiest. Following each character or word as they are revealed would be a lot more difficult. 

Screenshots and a detailed description of the animation or a storyboard would help me help you. I'm not going to bother writing a sample expression until I know exactly what you are trying to accomplish.