Would you be willing to get a Rotorcraft CFI? I imagine that with your experience you could knock one out fairly quickly then teach for a school with both helicopters and fixed wings. Usually working CFIs get significant discounts on additional ratings. That could save you a lot of money, especially if you have VA options through a 141 school.

I know of a good one in Texas.

As far as the ATP written test course Envoy and Express are the first I've seen to offer the CTP training.