I would keep him in same room Missy will be staying. I would put carrier/container in the room. Open the container, let him come out when he is ready.
Have a litterbox and all in there with him.
I would think in a day he will be ready to explore.
I've done both ways to introduce. Behind closed doors and just let them out. If I just let them out, they went into a secure place when I left the house.
Eleanor and Cindy were last two do just be let out.
You'll know what to do