If they are going to take a few days off and rent an RV to go with you, then my first choice would be to get out of the Austin mess and head over into the hill country areas around Fredericksburg, Kerrville, Bandera, or even farther west. And then it depends on your and their interest. There are very scenic state/city parks with hookups but few amenities other than hiking/biking and enjoying nature. And visiting the quaint hill country towns. Then there are the full service RV parks with a lot of amenities. If she has lived in the area very long she can probably guide you in a good choice of places to go.
