My DS says it varies with them and depends what else they have going on that day, anywhere from 1-6 miles, sometimes with their packs, sometimes in boots. But they are all expected to train on their own time as well.
I run about 2-6 miles a week on average. My unit tends to do a lot of High Intensity Interval training so even though we may not run a whole bunch one PT session, we still get a good cardio session in.