Even that's doubtful these days. In my heyday I rode Sydney (ie Surry Hills) to the Blue Mountains (ie Katoomba) and back (that's 200km) for fun and 200km races for the jolly experience of it all, but 299 in a day? No, not ever. So to finish - let alone win - the Melbourne to Warrnambool (the 'Warnie') is simply miraculous, and these guys pulled off exactly that miracle.
I do wonder about the physiology of it all. I found that doing 500-700km a week gave me great endurance but knocked my pace down a notch. Which is to say I suffered in crits something fierce. But 200-300km a week was just perfect for club A-grade crits and my sprint came back. Occasionally I'd do 500, but anything above 200km was a bonus.
And come the track season the big winter road miles (Aussies do their road racing in winter) had built my strength up, so it was a case of simply dropping the miles back and sharpening up.OTOH if I'd had a slack road season I needed 400km a week and maybe some weights to get up to speed.
Even when doing those almost-slack 200km weeks I could still jump on the bike and ride Sydney to the Central Coast and back in a day (200km) with my time each way almost exactly the same. I had 'endurance memory' locked into my legs, I guess. But I seem to have lost it in the last 7 years or so. Back then I was knocking over 100km in 3 hours or less on my own, now I'm cramping after 50 and crawling home. Could it be my age? Nahhh. I've just slacked off the miles, haven't I?