Tonneau vs topper vs open bed
 

I know it is of the opinion of some people that we drive big trucks with big engines and therefore shouldn't be concerned with fuel economy but I still would like do do as well as possible. I currently have an ARE topper on my 2006 long bed F150 2WD reg cab with the 5.4L. is the fuel savings from reduced drag of an open bed offset by the added weight of the topper? Would I be better off going with a roll up tonneau? Is it all a wash? What do the experts say?

The topper that you have should probably get you the best mileage. The tonneau is second. The open bed is last, but still not bad. Between any of these, you're not going to see much difference unless you do a lot of miles on the highway. Some people say that the best is an open bed with the tailgate down/off, but that's a myth.

What kind of fuel mileage are you getting? What percentage highway/city?

Make sure your tires are aired up.

Last fuel up I got 13.7 MPG all city driving. That is down from the 17.3 I got back in July when I first put the topper on. I'm wondering if that is due to winter blend gas. I have the tires aired up, check regularly.

Yeah, winter gas will always bring down your MPG. Plus, the cold weather makes your engine burn inefficiently until it's fully warmed up.

Sounds like normal numbers. If you're doing all city miles like that, it really doesn't matter that much what you have on the back. It doesn't seem to affect fuel mileage much until 45+ MPH.