SAR theory has some general help.

"Behavior Facts for Autism
“Bolt and Run” for no reason
Certain times of year or more prevalent
Early June
Late August
End of December
Hotspots
Attracted to water
Busy roadways
Dwellings – may peer into or enter
May not answer or come when called and will hide intentionally
May not be communicative"

www.operationtakemehome.org

"Quick Facts for Search and Rescue Professionals

Make sure you understand the degree of Autism you are dealing with. It will make a difference in dealing with the person when located.
Find out if there has been anything that has attracted the attention of the person within the past 24 hrs. Have they been obsessed with a location or object, at a location, within that time.
Do not expect the person to reply if you are calling their name. You’ll most likely have to make visual contact to locate them.
On many of the searches we have had, the person has hidden from us.
Check any location that has water, such as, pools, ponds, lakes, rivers, et al. immediately. These are points of attraction for those with Autism.
Remember that someone with Autism will, most likely, not experience fear , as we do. Don’t discount searching any location because you feel a reasonable person would not go there.
"

https://www.autismspeaks.org/family-services/autism-safety-project/first-responders/search-rescue