I have two 1985 Honda Sprees that get 98mpg and a 1982 GS1100E that gets about 33mpg.
For some reason I'm not really excited about ecomodding the Golf. I feel like I'll get more % results from working on the truck.
I use a iphone app called Gas Caddy to track my fuel usage (on all the vehicles). But it's kind of hard to interpret since I use the truck for such a variety of activities. Since I have a hour meter, I was recording the hrs vs. miles to get a average MPH for the tank, but I stopped doing it because every tank was 25-30 mph average.
The hight spot when I bought the truck was the drive home. A partial tank of 160 miles highway. The rest is either commuting, pulling a trailer, or a boat. The worst was when I was putting a 8,000lb boat in the water every day and towing it over mountain ranges.
Ideally, I'd like to build a "fastback" or "aerocap" if I can figure out how to make it cheap and look decent. And then the rest of the mods will be "stealthy". Like underbody coroplast and behind-the-grill blocking.
I'll be sure to document everything I do and post it here.
-Kevin