One point on cruise control:
I don't know what terrain you typically drive in. If it's literally flat as a board, then cruise control is as good as it gets. But if you're regularly going through elevation changes, an attentive driver can beat cruise: "constant throttle" is more efficient than "constant speed", and the average speed of a trip with either technique will be close to the same.
My advice to you would be: 1) track your mileage (at fill-up time - meaning full fills for accuracy). You can't manage what you don't measure.
2) Aero mods, since this vehicle mostly lives on the freeway, and drives at high speed.
- Have you pulled the roof racks off yet?
- Youv'e got a hitch; if you're handy (suspect you are since you're schlepping steel & plywood around), a hitch-mounted boat tail would pay dividends. EG:
http://ecomodder.com/forum/showthrea...ibe-22780.html
There are many more. Some quick & easy, others more involved. I'm sure you've perused the other aero modification ideas in the tips list:
65+ Vehicle modifications for better fuel economy - EcoModder.com