Here is one tip that I got, and will pass on. People don't always look at kids yelling. Thinking they are just having a temper tantrum. I told my gang, that if a man tries to take you, Scream, he's not my dad. or if a woman, she's not my mom.
We also do the buddy system in the bathrooms. We do a lot of road trips. The 5 boys go into the restroom together, and they come out together.(THere are many stalls in the bathrooms on 95, so there is plenty of room for all of them) If they leave anyone behind, they must come into the ladies room with me. (Never had to do that yet)
Your local sherriffs department should have a kit to collect your own identification kit for your child. Keep them handy, and keep the pictures updated. (not like me. My son is 14, and I think his picture his was 10. Yes I am fixing this right now)
Hope this helps a bit.