That cat could be scheduled for surgery or may be undergoing a diagnostic procedure that requires that water be withheld. Larger hospitals have more equipment in-house. That doesn't mean that if some procedures like an EKG, for instance, can't be done right there, that the hospital is substandard. Establish that the doctors do have access to diagnostic tools or specialty services either through teaching hospitals, referral centers, a central hospital, or mobile veterinarians, and that they are willing to use them or make the referral when necessary. Keep in mind that how you are treated and how your questions are answered does reflect on the quality of care at a hospital.
Many vets offer boarding.
They may board both dogs and cats, only cats, anyone's pets, or just their clients' pets. Even those with a no-boarding policy often make an exception for some clients, especially those with very old or very young pets, or pets with chronic diseases like diabetes . If a vet doesn't board cats, ask if he can recommend a particular kennel or cattery in your area. Check to see if the vet knows of cat care providers who could visit your home so that your cat can stay in his own environment while you are away. Chances are the staff knows someone who has this kind of business or may even provide this service themselves.