vortec with serpentine set up AC question

[beach]

I am hoping to find someone with AC experience...I am going with a new vortec/700r4 with the serpentine belt set up. The question that I need help with is, what all is involved with changing to the newer style AC compressor and going to 134a ...can I run the factory condenser, drier, expansion valve, and evaporator or should you switch all of it over to the equipment from a newer truck replacing the evaporator and expansion valve and going with an accumulator? All help and guidance is greatly appreciated.....