I have a trip coming up with a lot of highway miles and I was wondering, for budgetary reasons, what everyone is getting out of a full tank with a roof rack and light bar. I do not drive on highways much at all, so I do not have a idea of what to expect. I would really appreciate any input here form those of you with experience. I am sure many of you are running a similar setup, but actually travel more than I do on the highways.