Try to have your husband talk to her about making things easier on you. For all we know he and she have this "my house is your house" type mentality like my husband started out having. "Oh, help yourself to anything!" And suddenly everything we had was depleted and never replenished by our extended houseguests, especially expensive, gifted teas, spices, etc.
We've now gotten to a place where they chip in for groceries while they stay and we split meals out unless a holiday, bday, etc.
This was key to establish before we had kids bc once that happened our household went from the two of us to 5: us, a baby, and houseguest inlaws that needed food, shopping, rides, tv time, etc. At least we weren't going broke with 5 people eating all the time! And I don't feel taken advantage of and stressed out playing hostess for 1, 2, 3 weeks.

If your husband is present, you definitely don't need to be present. And you owe no explanations to her or husband ~ just do it cause you want to. If husband isn't home (but as long as she's capable) leave her alone - maybe half the time you would otherwise.

I don't allow guests to stay over. It is invasive to me and I refuse to feel uncomfortable in my own home. There is the whole world out there, and when I am "out there" I will adjust. But as far as my home- no. That is my place of comfort. Either stay at a hotel or stay at home. I won't say it like that at first, but if you get nasty about it then that is how it will be.

Sun-Tues - In-laws stay at your house. You cook, entertain them.

Wed-Fri - You and dh leave the kiddos with the in-laws and go on a romantic trip some place.

Sat-Sun - You and dh hire a sitter one night and take the in-laws out for a special dinner maybe to a movie or show. On the other day, you cook and entertain in-laws and enjoy their company.

I hate when friends and family use my house as a hotel. If you can't afford to travel independently than stay home and save for a hotel. Houseguest are disruptive especially after two nights. I've been in the situation where family will arrive 2 carloads and sleep in any available space. I absolutely hate it . After two nights I no longer worry about providing meals for people who selfishly want you to accommodate their travel needs and schedules. I also no longer willingly allow others to dictate when they chose to travel and stay at my house. Nine months pregnant those requesting visit have gotten " sorry but this is not a good time for us". Extra laundry, cleaning, cooking and entertaining will not be forced upon me because of their feelings of entitlement to free housing. I now blame myself for being a hostess that provides unlimited hot meals and entertainment.So now I only do what I feel like doing. Sometimes you need a break. I never stay at anyone's house when traveling because I like the privacy and independence of staying in a hotel. It's not your responsibly to be the family hotel.

We plan all our vacations and trips around staying with friends and family. It's great!

are there nice hotels where you live? Are you willing to pay or do in laws have lots of money? Will you pick them up and take them back? If so, that's fine.

Or are they broke and you aren't willing today? Or is the nicest option nearby some crappy days inn or best western? Or will you make them rent a car bc you are not willing to drive them? Then no, you need to let them stay with you.