A c4 tranny is doable for the shade tree mechanic. It requires no special tools other than your regular wrenchs, sockets etc, but you will need snap ring pliers.
The kit to rebuild is decently priced, and so is the torque converter. Just clean everything really good and go at it. The key to a proper shifting tranny is setting the tolerances like the bands and making sure its spotless of grime during reassembly.