I did 4 this past weekend. I played the IDGC Ironman (Steady Ed, Warner, and Jackson) before lunch, went back to my hotel, did some homework for school, then played Riverview. Got the 2 at the Hippodrome the next day.
I'd say that the 54 holes at the IDGC is equal to about any one day (80 holes/7 or 8 courses) of those mostly flat Minnesota courses. Those IDGC courses are for real men only!