Teary-Eyed, when my son was younger and often out and about because he was not allowed to be home, there was no texting so I had to wait for him to call me. Often he didn't. Often he still doesn't. It taught me something about him and most difficult children.
They are very me-centric and do not spend a lot of time thinking, "Mom may be worried." It is more like, "Mom is a witch (you know what I really wanted to type...haha) and she threw me out. I'm not calling her until I'm good and ready." In their differently wired brains often they do not see that we are/were scared of them and that is why they can't live at home...or that they broke the law while in our home. So they teach us a lesson by not communicating with us or doing so erratically.
That's some difficult children. Others just don't think about us at all. I have learned NEVER to ask my son to call me or I worry if he doesn't answer his phone. This is even in the present, with him having a home and being in his mid-30's. I still think he could tick somebody off enough to get into serious trouble. If he happens to do so, I can't do anything about it anyway so I won't set myself up to worry.
I think telling them, "Call whenever you're settled" is better than "Call me when you get there." Do difficult children ever just go home? They tend to live in the streets, maybe do a little drugs, get drunk, or just wander the streets and then finally go to wherever they have found to sleep. My son actually does not do this anymore and my daughter who did was a drug addict who is now clean. My worries are more based in, "Did Son go nuts and kill himself or somebody else?" Scary, yes, but I have to live with it. When times are hard for him and he is under stress, he freaks out in a frightening and horrific and dangerous way. I seriously have to distract myself in order to not think about suicide and if he doesn't call, I have to distract myself even more. But, in my heart, I know that if he truly wants to do it, he will and I can't stop him.
Hugs to you...waiting is terrible and our difficult children are terrible for making us wait.