Loading your VR Camera as 'Scene 0' and then loading all other content via additive scenes works well. However this required a lot of scripting and it was not easy to implement nor find the appropriate working Unity versions. We have created an Additive Scene Manager, which may help you with your VR Development:
[Asset Store Link]
https://www.assetstore.unity3d.com/en/#!/content/73891
[Intro Video]
[Free Tutorial]
As...
Asynchronous Additive Scenes for Seamless VR
[Asset Store Link]
https://www.assetstore.unity3d.com/en/#!/content/73891
[Intro Video]
[Free Tutorial]
As...
Asynchronous Additive Scenes for Seamless VR