This was definitely a stuff one for us,especially since we didn't even have room to give my mom her own room ! But she was actually pretty sensitive to my husband and I's need for some "time alone". She'd often encourage us to go out to dinner while she watched the kids or even encourage to stay overnight at a hotel once in awhile :) It was very odd to have to leave my own house in order to have time alone with my husband though, lol.
As for other boundries or rules, I pretty much gave up trying to have any rules or set ways of doing things. My mom was convinced that her way of doing things was the only right way so most of the time the battles weren't worth it. I did do little "lighthearted" things like tell her she couldnt' come in my kids rooms while I was doing a big clean up in them b/c she is a big pack rat and I am not. So I didn't want her in there, debating every little thing I decided to throw away, lol. But I said it in a lighthearted way, just poking fun of our differences and it worked out okay :)
Lisa