Do you have a family? If you do I would strongly think about the effect your new venture would have on them. At the very least it sounds like you will have to uproot yourself to a big city where there an airline base/flight training to have some sort of quality of life. It will not be easy. I bring this up because as an airline pilot I almost think it's not worth it starting over again at your age with a family.

I went through ATP years ago and they delivered as advertised. It's got to be the quickest route. But the flip side is it's up to you to finish training, they don't guarantee you will succeed even after asking for that much money. I know many guys that have checkride failures from there or quit flying altogether in debt. Out of all the guys and girls that were there when I was in training maybe not even half are at the airlines.

The local flight school is way longer and I'm not sure it's even all that cheaper. However what I would do is to go get your private license at your local mom and pop to see if you are still interested in taking such a road towards being a commercial pilot. Don't commit to big schools like ATP unless you really want it. Worst comes to worst you don't like it and you just have your private to fly around on the weekends.

Pm me if you have any other questions.