I am embarrassed to admit, that I am now no longer certain about dates and precise times. I'll root around for my logs, but this was all about 20 years ago.
Anyway, the two year period was from 89-91. I'm sorry that I cannot recall specifics, if that's what you're looking for. In some sense, though, it doesn't matter, you know? If you're looking for inspiration, then rest assured that I am an example - as is Wejo, by the way - and, hell, hundreds of others, of the power of moderately paced high volume training. If you want a guarantee, then, well... I'm not sure I can supply it.
Does this sort of training result in big improvements for everyone? I don't honestly know. Will it turn any ugly duckling into a beautiful swan? Well, from my own experience it will turn an ugly duckling into a less ugly duckling. I was never a threat to win big races, or even to win small ones. Can it turn an ugly swan into a beautiful swan? Yes. Check out Bill Rodgers' logs on Hodgie-San's site. If this training will give you improvement how long will it take to do so? For me, it took a matter of months. But, I had some mileage in my legs already, and I wasn't in college when I undertook this training. What's the takeaway? What will happen if you start to run high mileage? Well, there's only one way to find out if this approach, this running a lot more, will catapult you to greatness. What's the path? Ian is on his way. If you are inspired by this thread, joiwef, then you should put on your shoes, get out the door, and start on your way too.