Can you be a bit more specific? Perhaps narrow it down to one continent at a time, or preferably one country? There are loads of places with 172s but it depends a bit on how you want to go about this. Any ATO with a 172 in the fleet will be able to do this, but depending on the country the options for exercising your privileges will be different. It mostly depends on the country you want to fly in, the time you want to spend there and the registration of the aircraft concerned.