Glad to hear the setup process went well! Re: 16.04: we recommend using 16.04 as the host OS when setting up GCS just because it's the latest LTS version of Ubuntu so people should hopefully have better experience overall. But since we try to use Docker as much as we can, some of the Docker container will use 14.04 (e.g. ROS).
One more thing: we have an experimental and very primitive support for rovers which we tested on Erle Robotic rover with APM. The "primitive" part basically means the vehicle is controlled via RC override messages rather than proper pose messages. Let me know if you are interested in it.