The best choice in my opinion is the VW 1.9 liter diesel without a turbo and
an aircooled transmission (for proper gearing). Excellent torque, longevity,
very simple and affordable, any diesel mechanic can fix it (who fixes a
Subaru Vanagon in the middle of nowhere on a long weekend?) no turbo to kill
the engine prematurely. Fuel ecomony in the high 30s low 40s mpg, capable of
200k before rebuilds if not longer.
Greg