Transmission Cooler Line fix 1972 C10

[OlSmokey]

So I went to a mechanic down the street from me, and the transmission cooler line is leaking, and as well as the drive shaft carrier bearing is extremely worn out and I need a new one. With labor and parts and tax, is $350 a reasonable amount? Or is that way too much? I'm in Arizona by the way.

also a 2nd question, how hard would it be for me to fix the transmission cooler line myself? or is that something that you need to have special experience for?