By agreeing to an EFTA Norwegian style deal, of sorts, we would be remaining in the single market, therefore accepting the four freedoms; goods, people, services and capital. We would also guarantee UK citizens freedom of movement at home and abroad with continuing European citizenship.
There are still downsides though; access to the single market is partial in a sense that fisheries and agricultural are excluded. As an EFTA country, we would be sat outside of the EU Custom Union; leaving us subject to European Court of Justice laws and still subject to bureaucratic custom checks.