DS has a tendency to wake between 5 and 6 am. 6:00 I can handle but anything before that is so early! I'm tempted to give him some milk, a snack and turn on a show and go back to bed. Our home is small and I can hear what's going on in the living room from the master bedroom. Would you be comfortable with it? He's 4 for those that can't see tickers. The kitchen is gated off and there are childproof locks on the doors that lead to outside that are way too high for DS to reach so he couldn't get out of the house.                 
                             
        
Re: What age to get up alone?
He's getting plenty of sleep IMO. He asleep by 6:30 so when he wakes between 5:30 and 6:00 he's fine. 5-5:30 is a bit early but it's not often and usually only when he has a full pull up.
J. and A. often wake up early. They either play in their room or the living room. They let us know if they need us. Both their room and the living room are childproofed. And we can hear them from our room.
It doesn't even bother me that they could theoretically go outside. (I mean, J. can open the door. If he went out, A. would follow.) If I heard the door open, I'd be up in about 0.5 second to catch them.