Modern parts.

[MRiesAP]

So was playing with an idea in my head last night... as I am not looking to do a original restoration but a riding and functional bike first. Does anyone know where to get or alternate parts that fit to modernize the brake system to disc? I understand that i would have to replace the wheels with this type of modification, and Update the suspension to a stronger system? I am a heavier guy so would like a little more tension in the back, either a stronger spring or a gas shock maybe?