Thank you for all the replies. I am really at the end of my tether with all this. I have agreed (felt obliged) to spend the day with her next Sunday. She is already trying to tie down times, what we will do, etc. We are not going to an event, it's just a day together. It's already becoming draining.
As someone up thread said, my weekends are to get over the working week and plan for the week ahead.
@Rasputin123 she can then sort herself out. Be it making a Christmas wreath, a day painting or pottery class, yoga retreat, looking up an old friend, seeing a current or ex work colleague, visiting a relative, babysitting whilst you and DH go out, decorating at her house, reading, joining a gym, going for a walk, having a spa day, doing a park run or volunteering somewhere etc she does none of this. She won't do anything alone or go anywhere alone. She has no hobbies. She doesn't own any books. She doesn't belong to a gym or any clubs. She does nothing except expect friends to spend their weekends with her (day & night) going for lunch/dinner/drinks/shopping.
I agree I need to tell her no and in enough time for her to ask someone else to do something with her. She is just relentless. I feel I can't do anything without her wanting to know about it