Questions for horse people (please save me from the quicksand of research)

[ritaxis]

This fellow is living in a world that is rather like ours in 1890. He's working as an itinerant photographer and he has a boxed-in wagon and a largeish, bad-tempered horse. He's only modestly skilled at handling horses, though that might be ameliorated by the fact that he's a shrewdly manipulative person in general. What should I know?

How much and what sort of feed can my fellow get by with at minimum? What about water? How often does that horse need to rest? How long does it need to rest?

How does the horse's bad temper manifest itself? How do you placate a horse who doesn't want to take your wagon somewhere? (yes, placate, not intimidate)