Buy the TransGo HD-2 kit for the 4L80E.
Cryo'd parts is a good idea
The year of tranny you have is good.
The Sonnax reverse boost valve is a good addition.
Good quality Alto red fricrions work well with standard steel plates. I am not a fan of kolene steels.
A quality rebuild with the proper clearances and fresh bushings the tranny should work great.
Dont worry how old you are... it is the mileage on your body that adds up.