[Cotton]

Welcome! Other members have more experience with this than I do so they will be able to give better advice than anything I can recommend. In fact, I have never been able to find my robo's toileting area, either, if in fact he has a specific area. I have to clean the cage all at once. Plus, he moves so fast that I have to do it with him in the cage. I stopped trying to take him out because there was a risk he was going to get away and/or injured. His speed is incredible. I change the Kaytee/Carefresh slowly, working around him, and leave as many of his toys in there at one time so he has something familiar in there while I'm disrupting his home.

Too much bedding/substrate doesn't sound like a mistake. It's probably comforting to your hamster to be able to burrow. Also, is it possible she is coming out more often than you realize? Mine (Finnegan) is so quiet that I only discovered how active he really was one day when I reading close to his cage and saw him come out repeatedly. He was quiet, though, so I wouldn't have known if I hadn't been sitting there.

Enjoy your new hamster!