Building an AR/non-AR app

I'm about to start my second AR game and I'd like to make it conditionally support AR. I'm unsure about the best way to go about this. Should I make an app with a pair of view controllers and switch between them or could I use a single view controller but rebuild the sceneview and AR session while it's running?

Is there some other aproach I should be considering? I hope this question makes sense. I'd ideally like to be able to switch seemlessly while loaded models and all my gamestate remain in memory. I'd like to avoid having to do a complete restart if possible.