I thought about posting a similar thread last week, regarding to this topic. Hopefully, this thread will help.
Anyways, for now, just
volant intake, helper leaf spring, and custom magnaflow exhaust system. The
camper top is too dam heavy, so im thinkin about
replacing it with a soft cover to improve the mileage.
Edit: I have a manual and keep it under 2,500...19-20mpg on average. I do about 80% city driving. I keep it below 60mph wherever i go and avoid the highway.