You should change you oil at least once a year, so if you run less than than 15000 miles you can save a little money using a good brand name diesel oil ( sams club sells Shell Rotella T) and buying your filters online from someone like truckhelp.com Buy enough to get free shipping which by the time you get all you filters ( including generator ) and a spare set of fuel filters to carry with you, you should reach that . As far as mileage you should get somewhere between 8 and 9 mpg towing . It will tow your crv like its not even there.