If you have a contract, you should follow what it says.
If you don't have a contract, you aren't required to pay her during that time...however, those hours are difficult to fill. It would be kind of you to pay her when you're out of town. She's still available to work. She still has bills to pay.
When you're out of town, you could ask her to come in and do other tasks - collect mail, cleaning tasks that fall under her responsibilities - but unless you take off several weeks, just give her the week paid. We all need a break sometimes.