I used to fear them due to their size and strength. While I'm not an equine zoo myself, multiple equine zoos with mares have assured me that generally they are easy tempered with humans and almost never kick you, unless you legitimately give them a reason to. Mares like dogs, can form deep bonds with their human companions. Once this bond is formed, hurting you is the last thing on the horses mind. They're more likely to try and please you, sexual or otherwise.
With that being said, this is only testimony from other horse zoos. I honestly haven't stood next to a horse since I was a kid. I like to meet a horse again in person. If she'll have me, I'll have her. But I honestly wouldn't mind just staring at their beauty.
But hearing this testimony laid a lot of my fears to rest. Hopefully, you'll meet some nice equine zoos who will do the same for you.
If you have a phobia of being trampled, while unlikely, you could start your zoo journey with a mini mare once you get your own land and the appropriate equipment for their needs. Mini mares can be as light as only 160 lbs.
With very rare exceptions, a horse isn't likely to kick a person unless surprised - which is fairly hard to do, considering the fact that as prey animals whose main defense is "get the fuck outta dodge!", they pretty much exist in a near-constant state of what a self-defense instructor would call "condition orange" - the only "higher alert" condition is red. A kick that's actually aimed at a human is a very rare thing, though a human pushing his way into a scuffle between two or more horses might catch one if he's damn-fool enough to wade into such a situation.
A horse MIGHT bite a human, but usually, it's less an actual bite than a case of "Oops, got fingers/some meat on the palm along with the snack you were offering - sorry..." or "Oh, yeah... That's the spot! Scratch harder! Feels so good I just gotta share <CHOMP> - Hmmm... Sorry, forgot you two-leggers ain't got hides as tough as mine..."
As for trampling a human, unless there are several in a group, all in full-blown outright flee-in-terror panic mode, and "forced" into it (a human blocking the only exit from an enclosed space, ferinstance) a horse is going to do everything it can to avoid stepping on a human obstacle. Sentient or not, they've got a pretty good sense of self-preservation, and a leg injury (or having his hoof trapped in your ribcage...) is severely bad juju to a horse. They'll almost always dodge sideways, jump over you, or maybe knock you down as they try to leap over you, but actually stomp over top of you? Almost never happens. In general, only a horse specifically trained to stomp on a human target will do it, and while it's possible to train them for that, it's generally not something that's done these days, for obvious reasons. Such training pretty much ceased when mounted warriors stopped being a significant factor in warfare. This of course ignores the case of damn-fool humans that don't keep their feet out from under the horse's feet when in close quarters and get toes stepped on, but thats not "trampling" someone - that's nothing more or less than the human putting his bits and pieces where they shouldn't ought to be at the wrong moment. Most people pick up on that concept real quick, though, so it's rarely a significant issue.
Of course, all of these concepts go out the window in the case of a true renegade horse or a vicious feral, but then, only someone who already knows his business, and knows it very well, around horses should even be thinking about attempting to do anything at all with one of those.