Is there a bathroom, separate water meter and electric? Separate drive and bathroom in the barn? Are the fences all good?
Problems I see, is if this is near your house then you need to have boarder that has sense and will not be a nuisance and a problem.
You also need to check with insurance and see what they would recommend, as in does the boarder have to carry insurance and you all would just carry for property damage, or what?
And if you don't have separate meters for electric/water then if they forget and leave water running, or arena lights on? That will run up a big bill quickly. And if it is on same meters as your house? Then that bill is your to pay, or they will cut your meters off.
If there is no separate bathroom? Then that is major problem right there, as I wouldn't want them traipsing in and out of my house. And what hours is okay for them to stay until, or arrive, if the cars would be close enough to hear at your house.
Is there trailer parking? Where is the manure going to go? Do you have a manure spreader or will they have to do it? Which means a tractor too.
Will you let them bring friends out, what if they have kids and the kids bother the kids things that live in house, get in swimming pool, come in house? Will you allow them to drink and smoke on the property?
If you can find someone single/couple that are not idiots? Might work, but I would want more than just a handshake, and even then? Probably would not do it. Just too much hassle.
Horses make me a better person.