Off leash parks will be fully fenced and will not be near a kids playground. I think the pretty much everywhere has a leash law. Its in her best interest to have her dog on a leash for both her protection and that of the kids especially with a puppy who is more unpredictable. I think that you are well within your rights to tell her that you would appreciate her dog being leashed and as for smoking all you could do is politely say, "we would love to stay and play with your dog but I cant have the children around you while your smoking". she;ll either be offended or apologize because she probably never even gave it a thought.