What’s the incentive you need — NOT losing any money? That’s a pretty good incentive for most retirees. And if CD rates aren’t attractive, consider buying U. S. Treasury bills, which are paying slightly more than banks (only because the banks figure you aren’t smart enough to move your money!) Here is a link to that column.
And shall I assume that the remaining 20 percent of your investments are in a diversified stock fund? That’s not a bad idea, because over the long run stocks offset inflation. But you have to figure out how “long” your run is likely to be! Want to speculate: consider a gold shares mutual fund (Vanguard or Fidelity). With all this craziness in the world, the price of gold has been rising.