Establish rules. If you're too nice, you may wind up out of your bed, with an empty fridge and guests in your bathroom until the fall. Maybe even write "rules of the house" and place them on a table in the guest room. And if they aren't followed, speak up.
When you're staying with someone, you're more considerate about making noise, cleaning up after yourself, listening to what they say, paying attention to their needs and rising to the occasion even if you're feeling crabby, because you have to.