7:00 min/miles is a 4:21 min/km, which would result in 21 min 5K, 43 min 10K, 1h 32 min half marathon and 3h 3min marathon.
I can run a 7 min mile pace, but I can't sustain it for a long time, and when it comes to comparing running VS walking, 20-30 km feels like the distance you should use, as that's a distance most people could walk daily over an extended period of time (e.g a week).
I was never a great long distance runner, but I took it seriously for 1.5 years and I could run a half marathon just under 2hrs. The pace the whole time felt dynamic, everything went perfect, I was significantly faster than all the joggers by the river. I needed two days to recover, and the suggested place would have been 30 minutes faster.
With 7 min/mile pace, I would qualify for the Boston Marathon https://en.m.wikipedia.org/wiki/Boston_Marathon_Qualifying_S...