It's very common for kitties to not eat or use the litter box when in a new environment. My kitty was so stressed when we moved (5 yrs ago now) that she had fecal incontinence. If I was doing it over again, I'd confine her to a single room with litter box, food and water, a radio, comfy bedding, a feliway diffuser, and toys for a day or so just to get her settled and decrease her stress level. Then, I'd let her out while I was home to explore. I'd do this for a couple of days, then let her have free run of the house.