So I guess I'm sitting here thinking, "Why?"
Really, what's the point in going back if you can't go forward again.
Sure, go back, invest, it won't do you a lick of good. You'll basically be dead to the people you left behind in the future. It is nothing more than a novel method of suicide. You could just as easily buy a big life insurance policy, and go back to see %big_historical_thing% or whatever, and achieve the same results.