Since we are throwing out scenario's for an event we don't know for sure even happened, I'll toss out this one.
GP/BL have always had a spirited relationship. He is flippant/dismissive a lot and she responds by getting physical with him. He, being bigger and can easily defend himself, just laughs it off. She gets upset and goes off to spend the night with her girlfriend. This repeats itself over the years of their relationship and they both are used to it. Even on the cross country car trip the year before they don't struggle because they stayed in hotels and took it easy.
But now they are in a highly confined space for weeks on end. She is frustrated trying to start a youtube channel which isn't easy. He's dismissive. She's even more physical with him. This spirals upward until he is responding with his own physicality and soon enough it spills out in public and they get the stop in Moab.
He's getting frustrated with their relationship and the whole trip and tells his parents about the stop and they convince him to end the relationship and come home. He agrees and does. She has the van but she doesn't want to go on without him, so she taps into the money set aside for the trip to spend on a weeks stay at a hotel. Maybe she plans to end the trip so the money doesn't matter. Or maybe she is stuck with the van after he leaves and she doesn't know what to do, so she gets the motel to figure it out. Maybe she spends the entire week messaging him to come back.
So after she convinces him that she will stop fighting with him or that things will be better, he decides to go back. They don't get better. He is miserable. She is miserable and they spiral out of control until one day, while trying to set up a photo shoot next to a beautiful creek, he kills her in a rage.
