Wherever we travel , we always hire a car from the airport and hand it over back at the airport. Sometimes I have to hire a mini-bus depending on the number who joins with us. We never take packages. Except in the South Americas, where you can't return the car hired from Brazil in Argentia, Chile etc. So booked a tour from Chile using a friend over there. Very convenient and it was beyond our expectations. The drivers didn't speak English well but could manage. I can understand a bit of Spanish anyway.
Last May we toured everywhere in Mexico in a rented car (two internal flights as well). Only to Palenque took a tour as everyone advised not to drive that stretch alone.(dangerous as they rob you)
Just a few weeks ago toured Hokkaido - when I returned the car at the new Chitose Airport, had done 2800 kms in 11 days. Covered the entire island from top to bottom and left to right. No travel agent will do that.
Only in Tokyo better to take public transport. Drove for two days and got fed up. The last time I was in Tokyo it wasn't this bad.
Next destination to Japan would be Okinawa depending on my son's schedule.
One advantage when you have a car is that you don't have to stay in the cities itself. Just move a bit away and you get better hotels at much lower cost. Effectively you can recover the cost of car hire and fuel.
Always I drive never let anyone else. But now my son can drive. He's 24 , never sleeps during the day and if he's tired he has the sense to stop and let me drive.
The only places I have never visited is Russia, Cuba & North Korea. I was planning to visit Cuba on our way back from Mexico but my cousin in the USA when she heard it said that we will never see them again if we were to visit Cuba.