I agree, the proximity of the body to the van does seem significant. But what also seems significant in regards to that, imo, is how long the van sat there. If BL killed GP prior to the 29th, why would he leave the van in place and go hiking, only to then risk coming back to the van hours or days later? With other campers in the campground, it would have been all too easy for someone to have come across her body while he was hiking. And why would he want to hitchhike and be seen by more than one person, then be dropped off at the very campground where he knew the body was? I don't buy he tried to plan this as an alibi. If that was the case, he would have no reason to then run.
The more I stew over these details, the more I'm leaning towards what I posted on page 1 of this thread. I think they camped at Spread Creek after their visit to Jenny Lake. On the 27th, they ran to Jackson for money and lunch, planning to head to Yellowstone next. But something happened at Merry Piglets that caused a fight which continued to the campground, so BL left in a huff to hike, for a break, leaving GP alone at the campground, maybe with no phone or phone service. He hitchhiked back on the 29th by 6:30ish pm, got in another fight with GP for ditching her there, and that fight lead to her death. He panicked, picked up camp, packed the van, headed for Jackson to get gas, and booked. JMO.