1986 ford jamboree. piece of junk, 11 mpg on a good day
1989 vanagon. rebuilt everything. wasn't that bad on gas, but it broke down a lot. I was so happy to get rid of this van. Never again.
1987 toyota new horizons. Advertised as 15 mpg but it was more like 13 mpg. it really depended on which direction the wind was blowing. it was a sailboat. very underpowered.
now: 2010 toyota sienna. super tiny but 27 mpg highway (when driving 55 mph) and 18 mpg city. I did remove the roof rack and empty it out like crazy. great vehicle. super dependable.
next vehicle will be huge and very inefficient. not sure what I will get yet.