Tile preloading + force specific tile level for area

Before showing the globe to the user, I would like to make sure all tiles are in a specific area are loaded and the tiles in the view have the same "zoom level". With this I want to accomplish:

1) The user can freely move around in the area, without having to wait for tiles loading
2) Make sure the area looks uniform, by forcing a specific zoom level. In order to avoid: http://i.imgsafe.org/46f30dd.png

I suppose these issues are somewhat related, and don't think there's built-in support for this. Could anyone point me in the right direction to accomplish this?

Thanks! And loving Cesium so far, really amazing