I had difficulty with the same puzzle – finding the secret meetup / charging the battery on the fence. I was in one of those places where I had wandered around for hours and just wasn’t sure which puzzle I needed to be solving. I really suspected that Franklin was going to ‘zap’ the battery into life, so I just kept trying to figure out where I needed to put the battery down in the hotel so that he could access it. Wasted a lot of time on that endeavor! I did eventually look at some hints for the battery, and I’m glad I did – I don’t think I would have figured that one out even if given a long time.
I also wasted a lot of time having Ransome jump on the trampoline before there was a reason for him to be jumping. I was convinced that I had to click on one of the objects at the exact right time for something to happen, so I just kept switching which side the trampoline was on and clicking at different points again and again and again. Then when I did finally get into the safe, I felt pretttyyyy dumb.