I reckon they could run 50-70mpw, given you could only train one hour on weekdays and maybe two on the weekends. A lot of typical high schoolers top out at 16-16:30 for 5k, so I'll say this is the pinnacle of the average hobbyjogger that really really tries given their lifestyle constraints like being a Dad or having a job, etc.
TrackBot! VDOT 16:00 5k
TrackBot! VDOT 16:30 5k
VDOT for 16:00 5km: 64.6
Equivalent race times based on VDOT:
Marathon: 02:33:20
Half marathon: 01:13:15
15K: 00:50:56
10K: 00:33:11
5K: 00:15:59
3Mi: 00:15:24
2Mi: 00:09:57
3200m: 00:09:53
3K: 00:09:12
1Mi: 00:04:39
1600m: 00:04:37
1500m: 00:04:18
VDOT for 16:30 5km: 62.3
Equivalent race times based on VDOT:
Marathon: 02:38:10
Half marathon: 01:15:37
15K: 00:52:33
10K: 00:34:14
5K: 00:16:30
3Mi: 00:15:53
2Mi: 00:10:16
3200m: 00:10:12
3K: 00:09:30
1Mi: 00:04:48
1600m: 00:04:46
1500m: 00:04:26
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TrackBot! VDOT 11:05 3.218688k
VDOT for 11:05 3.218688km: 57.1
Equivalent race times based on VDOT:
Marathon: 02:50:26
Half marathon: 01:21:35
15K: 00:56:40
10K: 00:36:53
5K: 00:17:47
3Mi: 00:17:08
2Mi: 00:11:05
3200m: 00:11:01
3K: 00:10:16
1Mi: 00:05:11
1600m: 00:05:09
1500m: 00:04:48
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Those times seem about right. I've lived in three areas of the country and all three places seemed to have the same type of guy winning the local races (~16:00 5k / 2:30-2:35 marathon, thirty year old local runner who is probably sponsored by the local running store, Saucony Hurricanes or something similar).
Trackbot! VDOT 15:20 5km
VDOT for 15:20 5km: 67.9
Equivalent race times based on VDOT:
Marathon: 02:26:54
Half marathon: 01:10:09
15K: 00:48:47
10K: 00:31:48
5K: 00:15:19
3Mi: 00:14:45
2Mi: 00:09:31
3200m: 00:09:27
3K: 00:08:49
1Mi: 00:04:27
1600m: 00:04:25
1500m: 00:04:07
I am a bot. Info: habs.sdf.org/trackbot
Trackbot! VDOT 15:20 5k
VDOT for 15:20 5km: 67.9
Equivalent race times based on VDOT:
Marathon: 02:26:54
Half marathon: 01:10:09
15K: 00:48:47
10K: 00:31:48
5K: 00:15:19
3Mi: 00:14:45
2Mi: 00:09:31
3200m: 00:09:27
3K: 00:08:49
1Mi: 00:04:27
1600m: 00:04:25
1500m: 00:04:07
I am a bot. Info: habs.sdf.org/trackbot