There are barns that are built around horses, and their are barns built to attract "clientel". If it's a tie breaker, I'd go with the former anyday - as a beginner, you want your butt on a serene, unstressed horse; as a more advanced rider, it's a matter of ethics as well. Watch the lessons, watch the horses, get some education in best practices of horse keeping, then maybe one will start to stand out over the other.
To me, for example, sprawling farms with pristine fences and pastures virtually free of hoof prints, let alone horses, are very off-putting. A modest farm, where all the horses are out, with enough room to move and the ability to interact, would win.
I must admit that trail access would be a large consideration for me as well. Yes, it does fall under "clientel" (as it is my desire), but I also believe that horses do need to get "off the ranch" now and then for mental stimulation, and that moving over rough and varied terrain is good for their strength and coordination.
"The people" are way, way down on my list to consider, unless they instruct me. After a week of "people", I'm there to center myself, pay attention to my horse, and not heed other people's needs for a few hours.
Of course, that's just me...