Of course, I'm sure you'll clean up the house after your own family, that goes without saying....
I do think that making a meal is a great idea. Especially after they've gotten home from vacation! I don't know what time they'd be home on Saturday, but the last thing you want to do is make dinner ;) So to look in the fridge and see the makings for dinner would be so touching. Or if it's late on Saturday when they come home, they've got dinner for Sunday. Either way, I think they'd appreciate it, considering mom is probably backed up on laundry and the fridge is empty from being out of town.
I kind of agree about the gift card idea.... they can sometimes 'seem' thoughtless. I think there is a time and a place for them... ie. a teacher for classroom supplies, children learning the value of money, etc. I'm sure your friends would not be mad to receive one ;) but I like the more heartfelt gifts anyways.
Good luck!
Praise the Lord for small acts of Kindness,
KATIE