One think I forget is that all these different people have no idea that all the others are asking you too. I have an extremely tall stepson and he gets a zillion stares and questions all day becuase no one stops to think about manners or that others are making lame jokes about "how's the weather up there" as well.

Were I you, I'd put a sign of some sort on my door (even have your husband write/sign it?) not hide or anything and memorize a generic line, "I'm sorry, no" and keep on with whatever you are doing. Treat doorbells and knocks on the door like you would the phone; you don't have to answer and you don't have to be ashamed of not! Limit the time with your mother and if she gets to asking for money or something you don't want to give her, get angry/remember your resentment that she's not acting like a mother. Come up with a line for her too, "I'm not your mother and I will not discuss this subject any more with you, if you insist on continuing to abuse me you will have to leave, now!" and follow through if she keeps it up.