If your child has language, build some social stories to start discussing what it's like for people to move.

If your child has limited language (like mine), start taking pictures of the area particularly of the things that you think he'll be interested in. Then look at the picture book with him and talk about it from time to time. When you go to visit, make sure you go to those familar places and tie it back to the pictures.

Great suggestions, Jill!

I would only add one thing (IF appropriate for this child).

We use a PECS/VELCRO BOARD (small version) for a DAILY VISUAL SCHEDULE for our son in similar situations.
Have used this method since he was about 9 y/o...now 41!

(Picture Enhanced Communication) re any stressful situations like moving.....

We can't afford the computer program "BOARDMAKER", so we draw our own OR use pictures from magazines, actual photos.........

It's set up by our son re his daily routine. We ALWAYS use a small portable board for VACATIONS

I would also look up the website for their local Autism Society. They should have some great suggestions & resources for you.

Since medical aptmts are most likely stressful for your child, you may want to consider doing FUN local things before AND after them. :)