There's lots of ways to play it. One way would be to put everything into a range of blue-chip stocks with nice hefty dividends, in the 3 or 4 percent range, and just never touch the capital: those stocks only rarely cut their dividends -- but if they did, you'd just flex your frugality muscles and get by on whatever they return, until the dividends go back up. And in the long run they'll appreciate, and the dividends will get larger, though with a total return a little worse than the index funds. A nice psychological advantage to this is that you'd get the habit of treating your capital as sacred. You're *never* selling that stuff, so you don't even think about it. (I guess people do the same sort of thing with bonds, but I've never taken to bonds.)
Or you can just eat the risk and keep the index funds and ride the bumps. I'm kind of inclined to do that, because I'm more interested in handing stuff down to my kids than in minimizing my risk.
I think you really have to know what kind of investor you are. I've got thick skin: I just shrugged and held my stuff through the 2008 collapse, and didn't worry about it. Some people would find that impossible, or at least a stressor that would really torque their daily lives. You really have to imagine yourself, 75 years old and pretty unemployable, and think realistically about what you'd do if the market took a plunge at that point, and set things up for yourself accordingly.