Tips for 2 Old Ladies--Visit Zhangjiajie Park

Me and my Dear Old Ma will be in ZJJ in early September and we have 1 full day to explore the park. We will be up fairly early to get to the south entrance early (I think that's the closest one to the main city where our hotel is) by taxi or bus or guide. Once we get there, cameras in hand, where do we start? Walk a bit? Shuttle a bit? What to avoid? We want to be able to end up at an exit where there will be taxis to take us back to our hotel (or an express bus?). There's so much to explore, I wondered what was 'must-do' and what was 'could do' and what was 'meh!'. We like the idea of floating clouds and interesting pathways (with path stones?) and totally awesome bridges (old, natural, scary, etc) and pristine lakes with karst hills around. I suck at indoor photography so might pass on the Yellow Dragon Cave unless it's on the way to something else we have to see (it's lit kind of funny and my camera doesn't do well with funny colors). Suggestions are welcome! But, please be specific. Maps on google aren't very clear and dont' realy give us an idea of how MUCH walking there will be vs taking shuttles. Oh, and how can we tackle the Bailong Elevator without melting in the heat waiting for our turn? Is it a separate cost?