Hello! I’m C# developer, Unity3d developer and website developer in the past. I’m also familiar with Blender3d. I can do this job for you, but I need more detailed information about your project. Price and term can be changed depending on task info. Do you have design document for your game?
P.S. It's easy to do! You need just create script with static class where you can save state of all your scenes. I mean you should save all dynamic objects and variables in each scene. When you enter a scene you read from this script all you need. When you exit the scene you save all data to this script.