You'll have to nearly flush the entire system in the process of bleeding. If your brake lines are corroded, you'll have a hard time getting disconnected. Use PB Blaster and a line wrench.
Keep in mind, as these units age, the gate valve solenoids in them begin to corrode and fail. Make sure your wrecker unit has a 30-day warrantee. I did this once, and the unit from the wrecker was bad (different fault than original). I took it back, got a refund, and installed my old unit back in it.
I now live without ABS and TC on the Zilla. Have for 4 years. I have no TC on the SLE any longer, but still have ABS.
Suits me just fine.