I never thought he knew she was coming. I've always assumed, for some reason, that the element of surprise was an integral part of her plan from the beginning, even though I also assume she was confident in her ability to manipulate him once in his physical presence.
I believe she wanted to be 'intimate' with him (cough) that day because she wanted to be sure she was the last one. That was her way of owning Travis for all time in her mind, if you will, and thus was an integral part of the plan.
I think manipulation by guilt is a strong possibility, but regardless, manipulation it was, and 'it' succeeded, whatever the mechanism, as was reflected by the physical evidence.
There's also the fact that planting the pictures for any other reason, for any reason at all, directly contradicts her desire not be seen anywhere near him that day, or to think they appeared by accident through memory card swapping and just happened to fit falsely yet perfectly into what actually happened that day is just a rabbit hole.
I think her plan, if she didn't have to go with force at gunpoint, was to keep him off balance at every turn. For example, if she was actually in the house between 2-5ish and she actually brought photo CD's, I think she scratched them intentionally. Gaslighting. Here ---those CD's I promised you (Travis- maybe this will be OK), well damn, maybe you can't bring them up because they somehow got scratched? (Travis- WTF).
(Maybe even payback for the fight when she'd destroyed one of his PD CD's and he'd had the gall to express irritation about that)....
You asked why I thought what I do, and I've replied. It's nothing personal, but I'm not going down any more rabbit holes, nor getting on another hampster wheel discussion about June 4 or any particulars about that day. Like I said, I think we all bring our own stuff to this table, and I am well and truly done with the rich banquet we've had here for years discussing that day.