If I am going to crunch numbers and worry about mpg than I should sell the RV and stick to public transportation. If you have any kind of RV than you are getting lousy mpg. It may be better than some and worse than others but still lousy. If you don't like paying high California fuel taxes and don't like what California does with their fuel or gas, then stay out of California, its that simple. For me when I go into California I fuel up in Arizona at the state line. My coach carries enough fuel for me to go in, do my workamping job and get out without having to buy fuel in California. My 15 ton coach goes in uses their roads and leaves without paying their high fuel taxes. That is what works for me.