There is NO good solution for financing flight training. This kind of activity doesn't qualify for student loans, so you're forced to rely on personal financing.
Lowest interest rates for personal financing are home equity lines, but you need a home and a lot of equity in the home to open these avenues up.
Unsecured loans, like credit cards, have much higher interest rates. You may be able to get things done at 0% promotional rates, but those offers only last a year. Even if you can balance transfer to another 0% card to extend out the low rate for another year, these options usually don't offer balances in excess of 10k-20k at best... which is not enough to complete your flight training.
If you have the 4 year degree, get a decent paying job you hate... and use the money to fly. There's no shortcut or easy way to do this. You're going to stay poor while getting as much flying time as possible until you can do it for a living. You'll still be poor until you get a regional job. Even then, you won't be rolling in decent income for another few years.