delay function and interrupt problem

Damn. None of my code is usable. I suppose it would be fine now for just showing one page of text on every pushbutton back and fourth. What would you recommend as some type of layout? Case statements are definitely out of the question as you mentioned. I can now see how that would never work for getting out of the loop it is in with long pauses between each of the deisplayed text lines. I'm trying to wrap my head around the millis() function but it seems a bit to complicated since precision delays are not necessary but maybe i'm missing something important.

Thanks,
Mike