Pay at the regionals isn't great, but it's much better than it used to be. If you want to get to the majors ASAP, go to a regional. You'll check the 121 box and gain flight time quickly. Upgrade at the soonest opportunity with both the military and regional. Try and get to 3000TT as soon as you can to be competitive at the majors. Once you have that, try and upgrade to IP in the military, then you're just waiting for the phone to ring.
If you go to one of American's regionals, you have the guaranteed flow in your back pocket. You'd want Envoy to be able to stay away from the east coast.