You could dream of a two-year period, but it would be full of holes and plot skips, and the amount of time actually spent conscious in the dream would still equal about an hour. It could appear to be more if you accelerate time in your dream, but you cannot stretch dream time to any significant degree. Therefore, if you were to "live a lifetime" in a lucid, you could technically do it, but it would not be anything like what you have in mind. You would catch a fleeting glimpse of a few critical moments, only to be whisked away in another mass scene change.