You have other option other than regionals and ACMI. Assuming you've conslidated but have less than 1000 turbine you can probably get an interview at places like Jetblue and Hawaiian. Hawaiian has an ACMI style cargo operation that allows you to be mainland based. But If you really are interested in Atlas I will tell you that it's a great company, but it's not a time building job, they will tell you this in the Atlas forum and when you interview with them. You will get less than 2 landings a month if you are in their widebody fleet. Min guarantee is a little bit lower than ours (64 hours?) and you will often be blasting through 4-5 times zones every time you leave home. You also have to factor in that training is long, they tell you plan for atleast 90 days. Atlas does has DC that is around 12% which is great, you get widebody experience which is very valuable and you'll go to places that you'll never go to with Spirit or regionals.

In your situation, my advice is to hold on to your lottery ticket here, build some bus time and see what happens with the appeal. Regionals and Atlas will still be there. Flying will pick up eventually up just through attrition, and despite what all the doom and gloomers say, spirit isn't going disappear overnight. All that being said, if you can get on with another major, do it.