What is involved in replacing leaking iron drain pipes in a house with a concrete foundation?
Vertical sections of cast iron rarely need replacement.  Horizontal ones do.  I would get a quote(s) from a plumber that does/has connections with sewer line installations.

They should start with a in-line camera review.

Chances are most of your work will be in the (hopefully you have) basement and yard to the main sewer, but again, don't panic until someone runs the camera