Yes I think he was doing reconnaissance. Checking out the future crime scene, entrance, exit, parking, etc. Just as you outline. Also stalkers love to do surveillance. So high probability he was planting some devices, etc. You nailed it.If he was not actually planting some devices, he could have been checking on their alarm system, their Wifi signal, seeing where the windows were. He could also have scoped out the area- ways to approach, places to park, avenues of escape. Maybe once he was in the mid west again, he started snooping more online, asking mutual friends more questions, seeing the wedding video- maybe it all sort of "snow balled" from bad curiosity to a bigger obsession. We really do not know if he was there even earlier- checking their vehicles, snooping through their garbage? spying? I would think that some of Monique's closest friends would have known how she felt but maybe some less close people had no idea what had happened to her, so maybe he asked a lot of people questions, and until he approached some one who was really close, it did not get back to her. For all we know, maybe Monique thought he was still out west. (all speculation. my thought, since she ran away from him with her parents' help, she never spoke to him or contacted him. I would think if he got her phone # and called or texted, she would have blocked him and changed the # IMO)
In terms of her blocking his number automatically: I understand that most people here are thinking like non abused women. Women who are not being stalked. Women who are not frightened.
Terrified women might not automatically block the stalker's phone, or refuse to respond. They may be afraid of escalating the situation, and making the abuser even more angry and revengeful. They may also want more information about what is going on and why is the abuser contacting her again. This is usually the case when kids are involved, maybe a new marriage she is trying to protect.
So what seems like a simple problem to everyone else, is not simple to a woman who is being stalked. Also an ex wife may not understand the danger, that her abusive ex is spiraling out of control and in worse shape than when they were married. She may think she can handle the situation.
We don't know all the details, but I am trying to help people understand what might have been going on with a woman who has an abusive ex husband starting to stalk her. Or has been stalking her for some time.