What are the key elements that make a virtual race course on RGT Cycling engaging and challenging for riders of varying skill levels, and how can course creators balance realism with gamification to create an immersive experience that also promotes fair competition and rider progression? Are there any specific design principles or best practices that can be applied to create courses that cater to different types of riders, such as sprinters, climbers, or time trial specialists, and what role do features like terrain, obstacles, and weather conditions play in shaping the overall racing experience? Can course creators use data and analytics to inform their design decisions and optimize the racing experience, and if so, what types of data are most relevant and how can they be applied to create more engaging and challenging courses?