AC evaporator?

[fins2wheels]

So I have a leak in my ac in my 99 f350. I have been told that it is my evaporator core that is leaking and the dash had to be removed.I have been quoted anywhere form 500 to 700 to replace it. I would rather do the work myself but I have been researching and I am just lost, couldnt find out much about the location or removal of the evaporator core. Do I have to remove the dash or does it come out from under the hood. Either way it comes out does anyone have any tips or suggestions