While I'm not opposed to the idea of some realistic transport options for staff, remember that the game is designed around the idea that you include multiple staff areas around your zoo so the staff don't have to travel far. If you have three to five staff blocks, complete with staff rooms, keeper huts, vet surgeries, etc., spread out around your zoo, then you shouldn't need to worry about staff not getting around.
Hey, I'm an ex-zookeeper myself. Funnily enough my experience is the opposite; the zoo I worked in was large and had only one central administration hub with the staff rooms and such in it, though it had a couple of 'feed points' for food storage (they added an extra one recently, which is basically just a refrigerated shipping container full of vegetables and fruit for the gorillas). We used to get around in pickup trucks.As a zookeeper