Pushy family member

My husband's 65 year old, never married, only child, cousin is becoming a nightmare! She was always catered to by her parents and expects everyone else to do the same. Her parents both died about five years ago. I felt sorry for her and began inviting her to share Thanksgiving and Christmas with our family. This was meant as a kindness to help get her over the grief hump and she now just expects it and invites herself. Our college age daughters don't enjoy being around her because she is so bossy, nosy and opinionated. She is quite lazy, is NO help in the kitchen and just wants to eat and sit in front of the TV unless we're willing to take her out for food and entertainment and naturally we foot the bill. She also calls and invites herself at other times since she lives about 75 miles away. She always wears out her welcome because she stays for 2-3 days at a time. If you tell her you have plans she wants to know every detail and won't give up until she knows them. Then she presses for another date. Once when we had somewhere to go after she had been here for a day, she wouldn't pack up and leave until we were headed out the door. She shows up and acts like she is at a hotel as a paying guest. The last time she visited, she got up early the last morning, went to the family room which is next to our bedroom and coughed over and over until I got up and made coffee. She then proceeded to the kitchen, plopped on a bar stool and informed me she didn't want eggs for breakfast! I feel like I am entertaining a five year old!
She called the other day and asked what I had planned for Thanksgiving. When I told her I hadn't thought about it, she replied, "Well, let me know and I'll bring what I can." She lives within sight of other relatives and not a single one will invite her over for anything. I feel like I have opened Pandora's box. Help!!!