Would you be able to collect unemployment insurance? That would soften the blow.
Retired folks often keep three years of withdrawals in cash and other fairly liquid investments, such as CD's. This prevents draw down of assets in a declining market. In your shoes, I would want to something similar. I would consider the likely period of unemployment, the contribution of unemployment, plus the contribution of income from side jobs and investments. Figure out the likely shortfall and add in a safety cushion. Since you would not need all of the money at once, some laddered CD's might improve your cash returns slightly.
I would not rely on credit. In 2008-2009, many people had equity lines, personal lines, and credit cards cancelled or the limits were reduced substantially. As you point out, credit availability can be severely restricted just when you need it.