In the long run, it is determined by your journey itinerary as you can go to the jungle just before or following your tours in Cusco. From Lima to Iquitos you should have much more flights out there and probably also less expensive ones than from Cusco to Iquitos. Book https://griffinuueee.csublogs.com/32618233/new-step-by-step-map-for-peru-amazon-rainforest-tours