Respect for personal space after the wedding???

Both families live within 15 minutes of us. They know I won't answer the door if I don't know who it is- I had a scare where someone pushed into the apt. before we were married. We don't have a peep hole and I can't see who is at the door. My MIL does expect us to visit- and it can't be a 'stop over and chat' visit- it is usually a 5 hour meal!!!~
Gets annoying but we try to limit it. My SILs still live at home and tend to get a little too pushy- telling us where to look for a house, etc. I'm not used to that and its difficult to hold my tongue. I can't stand when someone second-guesses eveything we do!
As far as the nosiness, when we were first married, we invited the SILs over for dinner. One goes into the bathroom, and is in there a while ( meanwhile my Dh's family are like camels- they never seem to use bathrooms...). Next thing I know, I hear something fall out of the medicine cabinet (it always fell out and I hadn't found a better place for it) into the bathroom sink. I heard this while we were in the living room and knew what the sound was. Dh says 'maybe she was looking for an aspirin' but I KNOW otherwise. I will not permit them into the apt. if I'm not here- I don't trust them to not snoop. There have been other things, like looking through mail, etc. that make me feel this way also.
I love my DH but his family needs to get their own lives....

My MIL is in Fl, but my Mom is famous for showing up at anytime. I had to break it to her that it doesn't fly anymore. She was a quick learner & always calls now. Sometimes she's 5 minutes away when she calls but whatever