F-150kid

I have a 94 f-150 I am currently working through the minor issues with it! I would like to eventually add A/C as it did not come with it originally... It has the 300 I6 from what I could find I need the compressor evaporator heater box and serpentine belt... Is there anything else I will need? How hard is it to do the conversion? About how much will the parts cost for the conversion?

Thanks, f-150kid