Apart from tidying up the house:
- see what they like to drink and or if they prefer filtered water. My parents asked for diet pepsi and coffee for the morning. I picked up just a few groceries and sandwich fixings even though we ate out most of the time.
I also kept an eye on the towels and made sure there were plenty.
Do you have plenty of blankets and pillows or a comfy air mattress.
I'm not flamboyant as my other siblings who are famous for having BBQ's, horse shoe tournaments, a live band, etc. I'm even surprised they visited but then it was a chance to see the grand kids and after all the partying at my other siblings house they welcomed the peace and quiet. They enjoyed taking drives around the area, site seeing and unwinding at night with a movie.
I generally bring things to entertain myself. Access to internet and movies is a plus. I would always be particular about having my tea and if there was a comfortable place to sleep.