When i am out mobile and i pull up to the house i pull out my mobile and pretend to have a phone conversation saying that im there and such, then when i leave i do the same again. It just makes the people think.( also handy if the client likes to keep you chatting it looks like another appointment after them.) I do have a book with appointment times, addressess and phone numbers with someone at home too.
Another thing i do is leave my handbag and purse hidden in the van, also my phone, i have my van keys on a key chain that is clipped to me at all times, so if the worst happened i could run out and get away and call for help.
Always check your entrance ways again if anything untoward happens i also let the client lead into the house even if i have been there lots of times before.
I have got some regulars who i have been going to for years but i still do this, they have never mentioned it and so it cannot look too out of place.
One other thing that i have only recently started to do is when i go to anyones house i dont have anything to drink from them, i used to, my sister in law was doing some collecting for an agency and became chatty with one lady over time, one day she invited her in for a coffee, next thing my s-i-l remembers its gone midnight and there is noone around, the car keys, money handbag cards etc had all gone yep even the car. so thats why i dont drink at peoples homes, you never know.
On the bright side i love going mobile as its always different, keep your witts about you and you will be fine.