First I came to Thailand in 2016. I`ve chosen a car in rental24h.com with navigation and of course insurance. Because you can set on the map where you need to get and in any moment you can also control your location.
I agree that if you visit foreign country by rented car, you don`t know driver habits.
But for what I had traveled to Thailand? To acquaint with their nature, mentality, habits. The best way to see that all is to rent a car https://rental24h.com/thailand and drive wherever and stop whenever you want.