Re: how many miles per gallon do you get?
I finally added up all the gas receipts from our recent 30-day, 8,300 mile trip from Pennsylvania to out west and back. Below are some data points as an FYI to people asking about real-world MPG figures for vans.
Our van is a 1998 Ford E-250 EB 2WD, 5.4l gas engine, with a full SMB interior conversion and PH. We had two adults and an eight-year-old child. Not sure what our loaded weight was. Mileage on the odo when we left was a bit under 77,000 and almost 85,000 when we got back.
Driving was mixed between LONG Interstate sections to get us out west, short mountain-type driving in some National Parks, a bit of city driving mixed in, etc. Most miles were highway, though.
We got an average of 14.7 MPG over the entire trip and spent about $1960 (ouch). Gas prices ranged from a low of $3.19 down in the south somewhere (Arkansas? I can't recall) to $3.88 in the Chicago area on the way back. As an aside, we spent about $1600 on lodging/camping for 30 days, which included 11 days camping and the rest in motels/lodges/etc., so gas was definitely the biggest cost item of the trip.
Our lowest MPG was 11.4 on one tank, while we got a surprising 20.4 on another. I'm discounting the high and low outliers of 22.6 and 10.1 MPG, but I guess those numbers are possible. Normally it was right around 15.X MPG. The really low numbers were on the Interstates where we were doing 80 MPH for long stretches, and one tank driving around the mountains. When we kept the speed reasonable (e.g., 65 MPH) we got between 15-17 MPG.
One of these days I'll do a trip write-up for the forum. A great trip, and a great memory for our son! (And us, too, of course.) In hard numbers the SMB did not pay for itself, as we ended up staying in motels a lot more than we had planned, for various reasons.
Probably would have been cheaper to take our minivan and stay in motels each night, compared with the extra cost of running the SMB. But where's the fun in that? And, we would have missed out on some cool campsites, like this one in Black Hills NF (dispersed), where we woke up to a herd of cows mooing at us in the morning right next to the van! Normal for you western guys, I know, but pretty cool for us right-coasters. Best campsite of the trip.