There are better places to earn a buck and still go liquid in 3-4 days.
There is only so much that you really need to have in straight cash (though if you have a high yield savings account that is doing better than current CD rates, why not?).
No need to keep 6 months of living expenses in cash if you can keep 1 month in cash and the rest somewhere that is accessible in less than a month. Pio's suggestion of laddered CDs works, and even if you need more than what is expiring that month, you are only forgoing interest when you cancel them.