Have you looked into using Feliway? It comes as a diffuser, wipes, and spray. We always have a diffuser plugged into our boarding cat room. When I recently moved I bought my own diffuser and used it to help ease the transition for my boy, Voltron, as he DOES NOT adapt to change well AT ALL. It helped a TON... in fact, after we let him start exploring the rest of the house, he would often retreat back to the room with the diffuser as his "comfort spot". While he would be freaking out upstairs, down in the "comfort room" he was all purrs and headbumps.