I believe the CSA would have made a temporary alliance with Great Britain or France. Slavery would have ended because the overseas cotton market thoroughly finished it. There would have been much economic hardship (that happened anyway), but Northerners would have no heart to invade the South again. Instead of yankee carpet baggers, European entrepeneurs would have immigrated to the C.S. and aided with a genuine reconstruction. Black folks and white folks would have continued to live in peace and assimilated with less turmoil. And much sooner.
As for westward expansion, the U.S. would be in a very weak position to annex more terriorities into states after they made war on the THIRTEEN other states. Perhaps some of these western territories would have made an alliance and seceded from the U.S. Perhaps there would have been another war decades later to admit them into the CSA. Why would these people want to submit to the NE puritan yankees that waged a bogus war of attrition for the stated purposes of "preserving the Union" and "emancipation of slaves"?