I think everything your Hamster is doing is perfectly normal hamster behavior.
They sleep where they want. If you have a house that blocks or reduces light then I wouldn't worry about that being an issue. If it bothers him too much, he'll go into the house to sleep. Rooms can get too hot or too cold. You'd know it. Here is a guideline for temperature: (18 to 26°C, 64 to 80°F)
Also, this web page has some nice reading on hamster behavior and care:
Animal Care/Hamster - Wikibooks, open books for an open world