Then just like you have to do to have stuff for your normal sims to survive during their camping trip you'll need to do for pets. Brings a place for them to eat and play and a bed if you don't want them to sleep on the ground. My guess is that they won't be able to sleep in tents just because the sims team doesn't normally go back and do that sort of thing for stuff specific to a pack that not everyone might have. I don't have Cats & Dogs so I assume cats can go to the bathroom on the ground like dogs do so you probably don't need a litter box but if you don't want them to go on the ground then you'd need to bring that for them too.