You have it made provided you don't lose that firehose of an income stream.
Seriously, 4 years and 10 months to pay off HALF A MILLION $$$$ in debt? That's seriously awesome.
That also means that in another 5 years after that you'll easily have $750,000 in investments, plus a paid off house and cars and no appreciable debt.
4% SWR on that $750K is $30,000, which is almost half the $67,200 you're spending now.
Think about that for a moment!
In 12 to 15 years, depending on how your investments do, you would be set for the rest of your life. Maybe sooner.