https://www.gov.uk/working-abroad, "You have the right to work in any country in the European Economic Area (EEA) without a work permit if you’re a UK citizen."
So presumably you'd vote No to maintain this right and stay in the EU? I'm confused as that seemed contrary to the rest of your comment.
Parts of the UK could easily be overwhelmed by open borders with the rest of the Schengen Area. Perhaps Scotland will fair better, maybe it's less attractive to migrants. What is certain though is, with a Yes vote, that unless the rUK vote to become part of the Schengen agreement there will need to be border controls between Scotland and the Common Travel Area (CTA).