Hi Brian,
The original question was what would be fair to charge. I agree with Chris that 250.00 a month is steep. I feel for your situation, just think that it may be too much to be able to recover later. Of course, you are storing it in a shop, rather than a warehouse, and that is a more premium space. Plus... it is a default type of deal rather than a normal storage arrangement. Still...as much as it sucks, I think you should consider less.
I paid 350 for the entire off season until April indoors for a 28 brave. (In a place that stores mostly cars.) Maybe... 60 bucks a month?