To be a "bush pilot", and do it well, expect a lot of hard work, a steep learning curve and culture shock. I've seen many former military pilots struggle with company related "culture shock" when starting out in GA (and that's civilised GA, not "bush pilot" work) - it is really not for everyone. But there are some out there who just love this kind of work.
Australian or PNG CPL is entry level for those countries.
Have you considered Susi Air? There are a few threads running on PPrune about this company that will let you know the process and what to expect. Some great videos too.
https://en.wikipedia.org/wiki/Susi_Air
Pithblot