I really do want your advice. I want to make sure I go to her with the proper info to make her understand. With putting my foot down, my sister needs to be treated with padded gloves. She's older then me but acts younger when to disagree with her. Everything is very touchy with her and once she gets something in her head she doesn't budge. I was thinking of having some info sheets to bring to her but I'm not sure what the best place would be to get the most informative info. It urks me that she's like this. I'm sorry, I just needed to vent and get advice before I go. Thank You everyone for being so understanding and helpful.
Another thing I would mention, especially if your sister won't budge on the property question, is to vape in your car. You'll stay dry, and hopefully wouldn't have far to walk (I'd hope she'd accept you hiding away in your vehicle while it was in her driveway).
We all know this sounds kinda crazy, but the main point of the visit is for the little ones and in this specific situation, I'd keep a low profile and not rock the boat. If it was more of a 'neutral territory', such as a parent's anniversary at a community center or other, it would change the tack considerably.
I have not been in this type of situation, mainly because the family that I visit have not completely quit smoking, so having me stand outside with the smokers doesn't really bother me (I'd be out there even w/o my PV, alot of chatting goes on out on the deck, as all of us former smokers know well).
Hope this helps, and I do wish you luck.