Cat Crates? Please help!?

I'm moving into my dad's house, and I will be sleeping in his attic/bedroom. I have a Maine Coon and he loves to explore. My dad does not want him roaming the house at night. There is no door to close off the room from the stairs. I was wondering if a crate would be okay to keep him in during the night. He would only be in there a few hours because I have to wake up early and don't go to sleep 'til late. I was planning on buying him a harness and a long lead and just tying the lead to the bed post. But I am worried he might hurt himself by trying to get out of the harness. So my question is, should I buy a crate, big enough for his water, litter box and a small blanket to lay on, or the harness and long lead tied to my bed or someplace. Please help.