As for guests not going through the whole zoo - make sure your most popular species are the furthest distance from the entrance. It goes a long way to encourage movement.
I agree on having vending machines/drinking fountains to help solve this issue. I don’t have a problem with it personally at the moment, but my zoo is still quite small (at least for what I have planned for it) - larger restaurants with 2 food and 2 drink shops in busier areas (to reduce queue time) and smaller snack and drink outlets dotted around in between has worked well for me.
I agree on having vending machines/drinking fountains to help solve this issue. I don’t have a problem with it personally at the moment, but my zoo is still quite small (at least for what I have planned for it) - larger restaurants with 2 food and 2 drink shops in busier areas (to reduce queue time) and smaller snack and drink outlets dotted around in between has worked well for me.