Nosy MIL- opinions needed

My husband and I are temporarily living with his parents while looking for a house. We're renting out a bedroom/bathroom for the time being, and it's the only private area we have. We respect them, but expect it in return. I don't know how to confront her about being nosy.. She used to take out my (NOT full) bathroom trash, she tried going in our bedroom to get our laundry until my husband told her not to, that I do it. That isn't really an issue anymore. BUT, what really bothers me is this: we have a do not disturb sign that she has ignored, so I put "please text first", as she has woken me from sleep over things she could wake HER husband for. She still knocks, and has ignored it.. They also seem to still talk to my husband like he's 15. She has previously admitted to going through my clothing and counting his nausea pills when he was sick and left them on the table!! After asking me if that was okay, I said it wasn't my place in that time to say whether is was or not. I should have said something. | Any medicine of ours is now being hidden in our bedroom. | As for the constant knocking, should I write "Please text instead of knocking :-)"? I love this woman as my mother in law, but she's getting under our skin. **** Please keep in mind that yes, I know this is his parents' home, and I am respectful in the way I speak to her, but she is starting to drive me crazy. I haven't stood up to her because I don't want her to resent me. ****