As long as you're not going on the freeway, there aren't any tolls. I always drive up to Niigata when I go, and it still comes out cheaper than the train even adding up tolls and fuel.
Trains are excellent here for their reliability, but in Tokyo they can run at well over 400% of passenger capacity during rush hours. Nothing like being packed in like sardines on a hot train during summer so badly that you can't even manage to move your hand to wipe the sweat from your brow.
I wouldn't worry about not speaking Japanese in regards to driving. Many road signs are in English, at least as far as direction and destination or concerned. What you
will have to get used to are the roads, the manner of driving, and more than anything...the pedestrians. You absolutely have to watch out for pedestrians and cyclists here, as most of them certainly do not look out for themselves. You'll probably know what I mean after your first week behind the wheel.
