The kind of off road driving you are describing we call "off pavement", mostly graded gravel and/or dirt roads at relatively high speeds. For that a Forrester/Outback awd Subaru wagon would be good and it would get good gas mileage on those long trips you describe.
A Jeep Cherokee XJ or a Grand Cherokee ZJ with Select Trac (selectable part time/full time 4wd) would be good choices also but the mileage would not be as good as the Subarus. Good Luck!!

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PS An automatic trans would be a much better choice for what you want...just MHO