Based on your wonderful feedback, I decided to 'make it a great day'. I did not think about or anticipate problems this week. I consciously resisted the urge to monitor, make disdainful comments in my head, or save tidbits for later. I hugged SIL when she arrived, looked in her eyes, and said "I'm glad you're here" and when she left, said "thanks for everything, I'm glad you came". I neither ignored her wholeheartedly, nor engaged in-kind with inappropriate remarks or behavior. When she started to say something inappropriate, I asked her to repeat what she said, and then asked her if she needed me to help. In both instances, she settled down, and I realized that it was possible that something was happening that she didn't like and she didn't know how to absorb it or ask for what she wanted, so it came out rudely. Either way, my response was kind, focused on the immediate problem, and put a stop to her inappropriateness. I had games out, and she was able to engage in those. When she was being appropriate, I asked her questions and engaged. She asked someone else to get her another helping of something, but I was able not to have my typical irritated thoughts about that, b/c it is what it is, and was none of my concern anyway.
I also did a lot more prep in advance than I have in the past: shopping done by last week, most of the cleaning and all of the laundry was done; the table was set on Tuesday, most dishes were made yesterday, I set up my kitchen island lastnight. This morning, I took time to get myself ready first, not last. This resulted in me being far less irritable and exhausted. All of it planning and taking responsibility for myself, none of it having anything to do with SIL.
Today I followed a turkey recipe that got raves on Allrecipes. It came out dry and lousy. So I asked at the table, who really, really likes turkey, like would you have it if it wasn't Thanksgiving? One person. So I casually said, "maybe I"ll try cooking something else next year...or maybe we'll go out". A short discussion followed, SIL saying that she and BIL go out many holidays and it's fine; I mentioned that I have been hearing a lot of people do that and they like it b/c they can pick and choose what they want. SIL fished a little to see how serious I was, and I said 'oh, I don't know, it's just an idea I've heard about'. It was very low-key and agreeable. Right after that, guess what? Most people helped clear the table, and I got lots of complements. It certainly wasn't the turkey!! It may have been people responding to me being less stressed (and possibly more approachable to help) OR possibly recognizing that it IS a lot of work. Whatever the case, I was very happy with the outcome and happy about how I handled it. I learned a lot about myself that I could change, and I really turned a corner today. I truly could not have done it without the very kind and thoughtful feedback I got from this board, and I really appreciate all of you!! Happy Thanksgiving to everyone.