As a former special ed teacher, I had an eloper in my classroom One thing that helped was to find a motivator. This parter child liked paper clips. Each time a desired behavior or goal was met, he was allowed to play with the paperclips from my desk Is there a comfort item you’re little one likes that you could bring with you possibly?
My sister and I (I'm Audhd she is NT) were both serial elopers, our parents had an old leash from when my mum was a kid, after a couple times it was just a threat
Mary Barbera Turning Autism Around Book, she also has podcasts on You Tube for free you can watch might have that topic it's tough. My son did the same thing and still does, we have a backpack leash and I lost him at the Zoo for 4 minutes Might also try Agents of Speech they have free You Tube videos. We are going to be in ABA Therapy soon to work on elopment and hitting and in appropriate touching