Besides the backwardness of it all, the lanes are narrower as well. Most cars are sensibly smaller, however. In rural areas it gets positively silly. They merely pave the center of the road. If you encounter a car coming the other way, you both pop 2 wheels off onto the hard gravel shoulder.
Car rentals take some forethought and judgment.
They don't exist. These outfits charge extra for insurance, and have impossibly low mileage restrictions, after which it's 25 a mile. It's worth calling around. Mostly what is available for a reasonable price is some small Japanese thing, with manual transmission. Also, inquire on how restrictive they're going to be on driving on gravel.