Unless I am missing something, if you file a VFR flight plan then you just need a PPL. If you file an IFR flight plan then you need an IR also. There is no way around this (legally
).
The fact that many 3rd world countries like to route VFR traffic on IFR routes (because they don't understand the concept of people flying where they like) is a separate issue... it's no big deal because one flies to these places only with a decent GPS anyway... but one needs a GPS with the IFR intersections, airways etc.