I usually let them rebuild themselves and go on a mighty campaign of killing... What use is of a city but nobody to kill? Let them come at my sarissas again and again! makedonian courage will beat roman gold...

but other than that
I have never really tried moving roma around as i rather kill them than conquer them (filthy romans, you dont deserve to be conquered by righteous greeks/hellenes)

But if you do migrate them, ill put them somewhere along the lines of the alps and by those AI defense stack settlements. And then keep several forts to make sure they stayed on their side (bwuahaha)

Oh and yes epirote, koinon get moved around a lot. In facti was so inspired by one of the AARs about massalia, i sent koinon to epeiros (theyre proxy fighting romans for me) and epeiros to sicily, creating a buffer state that fights both carthage and rome (bwauahha proxy wars are fun)

Then myself? I just go conquer the barbaroi in the north and cowardly horse archers of the steppes =]