ive tuned into this awesome thread for years now,
and its really getting good. However as someone who has taken a 1981 vw on a similar trip, your MPG blows me away.
12mpg must be such a massive daily expense. I mentioned this a long time ago, but consider this, if you put in a diesel engine you could get 3x the fuel mileage.
it would only take a couple trips to make up the savings in fuel.
not to mention that you can tighten the drain plug reasonably and reliably.
oh, and you could have an engine designed to run over 100k miles