Simply put, difficult. Other countries don’t have nearly the selection of aircraft we have here. They have high fees, high maint and high fuel costs. Also, I believe if it’s a host country registered aircraft, you have to get a license in that country. Outside of military aero clubs, they probably are going to be host country registered. Some have language restrictions as well. Even though English is the official aviation language, they may require being fluent in their language. I remember checking on sailplane rentals in Germany, they required passing a German language test.