What is the best way to pay off $70,000 of back due taxes?

Remember, you're not going to jail. The IRS just wants the back taxes. And they're pretty agreeable to pay-off schedules. Give them a call and make an appointment to see one of their agents. Explain to the agent: Your current salary, current ets, current living expenses (all expenses, no matter how insignificant you think the expenses is). Between you and the agent, you'll come to an agreement as to how much you can pay per month. And sometimes, you can agree to pay every other month. And as long as you keep up the payments, they'll leave you alone and you can get on with your life. Good Luck.