JD has easy pace as 8:50 to 9:55 min/mi for someone with a 22:15 5km
9:32 - 10:41 min/mi for 24:08 5km
I started back a year ago last November and just ran 20 - 30 minutes around the 9:30 - 10:15 pace 3 times a week, took a few sessions to learn to run that slow.
I primarily run through first half of the year with a target ultra 100 race in June and then transition to more time on the bike. Right now I just get three TR sessions per week but run six days.
However, throughout the year I never run less than 30 miles a week. Even when hitting my target bike miles of 180 miles per week.