Is there buildings to trim around? That could factor in the estimate as far as time spent at the sight. If not, sounds like you could bust it out pretty quick. $250 might be a little high. Invest in a measuring wheel. It takes the guesswork out of property size. I have found that a lot of industrial sights are'nt looking for someone to manicure the lawn, only to keep it below the knees. They may not want to pay a lot. Bottom line is you can't always give estimates according to the size of the property. All the little things that can tend to keep you there longer than expected are what you have to measure as accurately as possible.