Regarding the gasoline scenario put forth ... I believe that we are closer to using alternate fuels for industrial/commercial uses and even residential heating/electrical usage than we are to having a mass marketable alternative to the gasoline engine.
Seems we should do what we can do cost-effectively (industrial, commercial, residential) as soon as possible, giving us some time to come up with a decent alternative to the gasoline engine.
If we are going to drive less (due to increased cost of gas), then we need those other alternative energy sources to provide other means of transportation, i.e. electricity powers urban rail service, for example. We'll need to make that electricity a viable economic alternative. Otherwise, we all better be prepared to spend more time not traveling anywhere.
If it seems inevitable that the cost of all kinds of energy will increase, then we better be finding some ways to generate the wealth that will fund those increased costs of living.