Thanks for your ideas, Serendipity. I think starting out with a routine that I can stick with would definitely be helpful so that the hamster gets used to what to expect. I sometimes wonder if I really spoiled Chiclet, spending so much time with her and getting her used to it on a nightly basis. It made it hard for me to go away at all without feeling terribly guilty and worrying about her. (Yet, for all I know, she was enjoying some peaceful "time off" while I was away!)
I like the idea of a timer for lights and TV noise. That would add both to their sense of routine and also perhaps a sense of somebody being in the house.