I will not tell OP not to do it, but I think there are two basic points OP should aware of if he/she decided to do this.

1. Toll road highways. In Japan all express roadways are toll roads, there is no such thing as “Freeway” in Japan where there is no toll. For example, driving from Tokyo to Nagoya (distance of 334 km or 207 miles) will cost you in toll of 8040 yen (US$ 79). From the perspective of the U.S. I do think this toll road fee such as this is bit unthinkable.

2. Gas price (or petro price). For example, the average gas price in Tokyo at this moment is 160.29 yen per liter. Which come out to be US$ 5.94/gal. The price is bit high from the U.S. standard.

I think OP should be aware of cost associated driving in Japan when planning.