Air conditioner freon leak - help

I have a leak in my A/C system somewhere under the dash area ( condensor unit?), I have been told it will cost around $700 to repair since the dash needs to be removed to do so. Does this sound like a fair price? Any help will be appreceiated. It is a 1996 4X4

Jeff

If the evap is leaking the labor to replace is about 4 hours, plus, evac and charge, even though the book time is 4 hours most times it will take longer,.

Thanks. Is the evaporator located under the dash? The mechanic said the dash had to be moved. Does this sound right?
Jeff

R/s behind the g'box, and yes the front has to come out.