As a former mainline member, I will testify to the fact that every one of the "7 sisters" of the mainline have individual congregations (and sometimes entire judicatories) that run counter to the prevailing stereotype of the denomination as a whole. When I was in the ABCUSA, more than a decade ago, most of our 270 congregations in the Pacific Southwest (nearly 200; some of them with 8,000 folks on a weekend) pulled out of the ABC over the homosexual issue.
But, a mainline congregation departing from a liberal mainline is not likely to move to the MOST conservative expression of that type of church. For instance, a disgruntled ABC congregation would probably not leave the ABC to become a member of the IFCA or GARB! I would suspect that a conservative Disciples of Christ group would go with the Christian Churches rather than the stricter non-instrumental Church of Christ. Nor would an ELCA congregation likely skip the LCMS in favor of WELS. So, if a mainline PCUSA congregation wanted to ditch the libs, they would still not want to join one of the confessional micro-denoms in the Presbyterian family. The PCA, while conservative, allows for some diversity that could appeal to a particular congregation, although the EPC might be a "better" fit for most of them.
Frankly, I'm a little surprised to see PCUSA folks going to the PCA for the reason of egalitarianism. Even congregations with enough biblical sense to oppose revisionist Christology (i.e., universalism) would probably swallow hard over restrictions on the role of women. The American culture has essentially marginalized non-egalitarians to such an extent that we are practically lumped with the KKK.