How often will people come and check in on them? When I'm going for vacations I have left Filou and Tigris in the apartment for up to 3 weeks- but with two visits per day. One one hand because of the litterbox- my boys insist on a clean litter box, on the other hand for some playing action and to see whether they are ok. Ok from time to time you have to remove a barfed hairball
It has always worked out purrfectly. They were very happy when we came back but there was no problem whatever.