You can usually get onto the course after play has concluded each day. I did that in 2011 several days and was not told to stop. They assume it's just players working kinks out after the round. Just don't do anything to draw attention to yourself.
i played the course with a couple DGCR members while they were doing distance competitions and such.
Champ FB //Champ Banshee //FLX Avenger SS //Champ Mamba //QJLS,JLS //KC Pro Cheetah //Stratus //Comet //Star Wedge //Pro Rhyno //Evo Magic