MPG on big square boxes decreases exponentially in proportion to MPH over 50mph.
You have to make the decision on what is more important on a 250 mile drive: Getting there 25 minutes faster or saving 2 gallons of fuel ($5 @ $2.50/gallon).
I averaged around 19mpg going 65-70mph with my 3.7/3.73LS T250MR. I did not have much weight on board, though. You are hauling a lot of weight with live bodies and multiple seats. My 3-person seat seems to weigh 200+lbs, so I imagine a full set of rear seats must weight 750lbs.
I don't think AC in modern vehicles has very much effect on MPG. In old cars, prior to 1980 or 90, turning on the AC would result in a 20-40% reduction in MPG. I doubt it's even 5% reduction now, I've never noticed a documentable difference with or without AC on my Sprinter, including running front and rear at full blast, and I keep tabs on every tankfull.
Highway MPG is mainly affected by total weight of vehicle and air resistance. City MPG is affected mainly by rate of acceleration and idling time (at lights). Best highway MPG is achieved by keeping it under 60, but wants to drive like that?! Also, as for weight, you're going to take what you need, so there's not much cutting down on that. A couple hundred pounds isn't going to make a difference when you're already at 5000lbs. In the city, accelerating slowly and timing the lights so you never have to stop rolling forward will get the best MPG. But everyone will honk and flip you off because you are preventing them from getting to the next red light as fast as possible to stop and wait for it to turn green. Because it's important to get there asap, for some reason, as if it might somehow add up and you'll get where you're going faster (in some parallel universe with different functions of time and distance that defy our laws of physics).
You have to make the decision on what is more important on a 250 mile drive: Getting there 25 minutes faster or saving 2 gallons of fuel ($5 @ $2.50/gallon).
I averaged around 19mpg going 65-70mph with my 3.7/3.73LS T250MR. I did not have much weight on board, though. You are hauling a lot of weight with live bodies and multiple seats. My 3-person seat seems to weigh 200+lbs, so I imagine a full set of rear seats must weight 750lbs.
I don't think AC in modern vehicles has very much effect on MPG. In old cars, prior to 1980 or 90, turning on the AC would result in a 20-40% reduction in MPG. I doubt it's even 5% reduction now, I've never noticed a documentable difference with or without AC on my Sprinter, including running front and rear at full blast, and I keep tabs on every tankfull.
Highway MPG is mainly affected by total weight of vehicle and air resistance. City MPG is affected mainly by rate of acceleration and idling time (at lights). Best highway MPG is achieved by keeping it under 60, but wants to drive like that?! Also, as for weight, you're going to take what you need, so there's not much cutting down on that. A couple hundred pounds isn't going to make a difference when you're already at 5000lbs. In the city, accelerating slowly and timing the lights so you never have to stop rolling forward will get the best MPG. But everyone will honk and flip you off because you are preventing them from getting to the next red light as fast as possible to stop and wait for it to turn green. Because it's important to get there asap, for some reason, as if it might somehow add up and you'll get where you're going faster (in some parallel universe with different functions of time and distance that defy our laws of physics).
