3:00 is OK. I assume you have lights and reflectors. If not then it is dangerous. As you said almost no cars, but a unlit bike is the last thing the few cars out there are expecting.

Also I would not start any earlier than 3, might enve suggest starting a bit later. The time from about 11 to 3 or so has more than it's share of drunk drivers. Drunk and limited visibility are not a good combo for targets on bikes.