Fatigue from golf comes primarily from the repetitive application of the stretch-shortening cycle in the swing and the loading of passive joint structures from being in a standing position for an extended period of time.
Rarely is aerboic fitness a limiting factor in performance (ask John Daly

), so I don't prescribe a lot of direct energy system training to improve golf performance. I may prescribe it to address body composition issues that may indirectly improve performance. Your HIIT should cover that sufficiently.
Bill
P.S. Please see the most recent issue of Men's Fitness for my feelings on "cardio".