From my understanding, NG vehicles have much less range simply as a factor of fuel density. NG is a gas (although compressed for such use), whereas gasoline and deisel are obviously liquid, so the same volume of the liquid fuels has much more energy stored in it.
As for wind, I heard a very interesting statistic that kinda throws cold water on the whole idea. The turbines cost more money than they recoup by producing electricity. Currently, it takes about 20 years or so to recover the cost of the turbines, but they must be replaced much sooner than that. Only government subsidies are making it a viable option. So in effect, we're footing the bill (through taxes) to pay for a technology that walks backwards in terms of return on material investment. Perhaps that will change in time, but the disparity is quite large.
Professor of Philosphy: "Only a fool is certain of anything".
Student: "You sound pretty certain of that, sir".