Folks have pointed out that the perp took an incredible risk in abducting JH when he did. Amost as though it was either "now or never" or maybe "now, or not for another week or month"....
Seems like a local perp wouldn't feel that time pressure to take such a risk in that situation. He could bide his time and wait and watch and make his move in a situation where there isn't a high probability of a random car driving up and catching him in the act. Even maybe grab her in less public location.
If this is an out of area perp who traveled a few hours+ to get there, and is planning on a weekend at a remote cabin in the woods with JH, then 11 pm probably represented a fail-safe point where either he had to do it or go back home or continue on to his cabin in the woods by himself.
Or potentially it's an out of area person who is in the area for whatever reason during the week and is headed back home Friday night and has to do it then or wait another week or more.
Course, could also be a local person for whom maybe the stars aligned at that moment and he took his shot. Just seems like a very huge risk that a local person would very easily be able to talk himself out of not taking, go back home and play some x-box and try again the next time JH works there.