ATP is not the only choice out there, I was active duty army and got out and saw the enormous cost of flight training and I'm thankful I used my GIBill for it. I spent maybe $40K after my PPL and got most of it back. The smart thing to do would be to also look at a college flight school option with your GIBill to come out with degree and be eligible for the reduced ATP mins for the regionals.
I worked full time while I flew and it's not easy financially especially when you have to shell out up front, but it pays off in the end, just keep cycling the reimbursement money back into training.