That might work. If I have to wait 30 minutes to charge (and not even a full charge) it has to have a longer initial range than gas. There is also the problem I mentioned above that the place you are going has to actually have a charging station as well, otherwise your range is cut in half. Can't got 250 miles if there isn't a charge there. Then you only get 125.
Finally, not sure how this works, but it seems that "running out of gas" would be a much bigger problem. Can't just get a tank of gas and bring it out to the car. I assume you have to get the car towed to charging station? Are there any other options? Any easy way (i.e. something I can carry) to get a charge away from home?