what do you look for in a boarding facility?

Private pasture and shelter. I would never board my horse at a place where horses from multiple owners were mixed.

When you ask for a private pasture what size would you prefer for your horse to have?

Doesnt need to be much, Place I boarded when I was working tugboats, Guy had about 20 acres and had a sturdy perimeter fence, inside that he had multiple 2 ish acre fields with a simple runin shelter and water trough. The horses got moved on occasion depending on grass. They were sorta pie shaped so they came together at one area so he could stand in nearly one spot to add water or hay. It was a really nice setup, simple efficient and cheap. Avoided so much of the hassle associated with multi owner horses all thrown together in one big 20 acre field.

So you keep saying. Every day. If you don't board, please let it go.

My opinions and desires for board arrangements are just as valiid as any one elses. Sorry if you arnt able to comprehend something other than, "The way we've always done it".
Always done it doesnt mean best.
Go cruise through this websight, over and over and over multiple posts, my horse is sick, my horse got kicked, someone elses horse attacks me, someone stole my stuff, someone was mean to my horse over and over and over . Its sickening. When the answer is so simple , cheap and easy.
Quite a few on this forum are too narrow minded to grasp the concept of doing something other than throwing every body into one big open pasture, and feel it is some insurmountable task to do otherwise. Sorry but I see it all the time.

In a way I can see a private pasture being a good thing but at the same time I can also see it leading to something that could possibly be bad. If one person notices that someone has a private pasture I would be afraid EVERYONE would want one. I, myself, would not be willing to section off my entire land to appease everyone who felt they needed their own private run/land/shelter (minus their own stalls that is given). On the other hand, I would be willing to have a piece of land set aside for people who would want private pasturing be it for their own reasonings or they have a problem horse and once that land is filled that would be that and if they don't like it they can find else where to go. Not to mention I think it would look a wee bit ridiculous having loafing sheds running rampant on the land haha.

Why would it look ridiculous ? You section it off in squares. Run ins in a straight row. The boarders in the paddocks don't have a stall. The horses stay in the field with the run in.

Here you go, an artist I aint. 20 acres divied up. The blue dots are water, the red houses are simple run in shelters, Boarders can bring in their own small portable prefab sheds for food or tack storage.

Nice drawing, I meant it would look ridiculous if I had sectioned off my ENTIRE property, 120 cares of nothing but loafing sheds and water troughs. :)

You could make a really nice place, round pen, maybe an arena, Also a track around the perimeter, even better if you bordered a place with miles of trails.