1. When exporting gpu cache there is an option to write materials but this does not work with vray shaders.
2. In the Maya software render settings, there is a tab for scene assembly, here you can set your cache scene to render full geometry files during render time, keeping your viewport manageable with massive scenes.
Just a point on the Scene Assembly section of the Maya software buffer, this is a very important and necessary option to have. If your rendering scene assembly with VRay you have to switch all the cache file to geometry before you render and if you have a huge town like we do it can be a pain to make sure everything has been turned on to use geometry before sending to render. Having this option for VRay is going to be a life saver!!