I could do it in under 3 minutes on my roadie. On my XC bike, about the same time or 1 minute longer with the wider tire of course slowing me down from 20 to about 14-15mph. 1.6 miles is a joke really but I am a seasoned cyclist too.
At 10 MPH, which is about normal bicycling speed, it would take about 6 minutes. At normal walking speed, which is about 3.5 MPH, it would take about 20 minutes. So figure somewhere in between for slow bicycling.