A friend of mine works as a GA ASI in Peachtree city - he loves the job. Get to fly on occasion, and works in a steady job, albeit sometimes mind numbing with repetition - sounds like flying the line. At any rate, he stated that once you get hired and in the system, it is rather easy to move around and promote. Was also told that like the airlines, the FAA has a lot of senior folks that will be retiring in the next few years, so additional opportunities may be present there.