When I was in college, I don't remember how this came up exactly, but I may have expressed to my mom something about how nice it was to come home, and that mom would cook my favorite dinner and might even throw my laundry in if she was starting a load, how I had this new appreciation for being cared for after going away for a bit. And she got this faraway look in her eye and said that back in *her* day she would take a night bus for 10 hrs each way to help plant the garden, weed, dig up potatoes, and chop wood. Not relaxing at all. And it really changed my perspective, because I think all my friends were basically of the same outlook--their parents pampered them a bit whether they came home or the parents visited campus, and no one went home routinely to help out.
And that's fine, really...that parents continue to help out their adult children, and that guests to try to make themselves helpful. I certainly try to do so when I am visiting someone and I see something I can do. But...I think it's different to expect this by default, rather than appreciating it as a favor on the guest's part. And in my mind that's particularly true with parents/mom; I had no qualms asking my sisters to do dishes, but felt bad when I found my mom already did before I got home. I realize my parental relationship is not everybody's, that regular visits are different than occasional visits, and that kids in the picture make help even more desirable...but I still think there's a benefit to seeing things from the "no one owes me anything" perspective and being pleasantly surprised when help materializes.
It's not like she's making (that much) more work for you. She sleeps in-zero work. She reads-zero work. She eats dinner with you-marginally more work to make 1 extra serving of whatever you were making anyway. You have to do her sheets when she leaves...maybe ask if she minds changing them before she leaves, or at least strip them off, and you take 5 mins of actual work to launder them. She sounds like a lonely lady who just wants to be around her loved ones...and doing so is probably good for her sobriety/addiction recovery. So maybe don't put her off visiting generally, though if Mem day is just too much, sure, ask her to move her plans forward by a week or two.