However how to connect PVC pipe to bell end of 4" cast
iron fitting that enters my house from the street? What's the proper way to do
this?

Check the Fernco fittings at your local box store, after making sure your
building code has approved them, of course. When you get the cast iron bell
ends free, measure the diameters. Much of the old CI stuff was pretty variable
in size and Fernco has oversizes for the inevitable surprises. Good luck.

Joe