Thanks for all the great advice.
What I am really looking for is this - what to do today, (still working, still saving) if there were to be a major market correction, with my current AA, which is basically all in my 401K? As I mentioned before, with other market downturns, I did nothing different, but I had a horizon of 10-15 years before retiring, so figured I would recover. Now, I should hopefully stop working in 4-5 years, not a lot of time to recover.