Miles per day isn't very telling. On a Sunday with light traffic on roads with no speed limit, you can average 120 mph and ride 1200 miles within 10 hours with reasonable ease. Riding through the jungle, 12 miles can be all you manage in 10 hours, and you will be totally exhausted. My longest ride in one day was 850 km, or 528 miles. It incorporated two ferry rides, and the highest speed limit was 80 kph / 50 mph. We set off 8 AM and got home 1 AM, so 17 hours from start until stop, including breaks - it was not a race to cover as many miles as possible, it was just a round trip we wanted to do. That was way back in 1989.