and you know what? if we could swing by for a slice of pie or cup of coffee, WE WOULD. But for MIL? if you aren't there for the whole meal - apps to meal to dessert to coffee, all separated by at least an HOUR? don't even bother.
If she TRULY "never sees you", then she should be grateful for any time you can visit, even if it's only for 30 minutes. If anything, the person annoyed should be you (and your husband). Not everyone would be willing to drive for any time or any distance just to spend a short amount of time with a loved one.
I know it's been said before (by you as well as the rest of us) but your MIL is a real piece of work.