I boarded horses before, it is a lot of work but with that being said if you love doing it why not try to build on that.
My sister boards her horse for 110 a month that does not include a stall, but he does have a barn for the horses as a run in. It includes hay. He has a tack room, wash area. I think she says he has about a 100 acres but he also has access for his boarders on his neighbors property of about another 100 acres that they can trail ride on. The place also is on a country like road which I would trail ride on anyday. I think if you stall its between 25 to 50 dollars more. My sister loves it there. There are no trainers but he has a listing with vets, farriers and I think trainers. He has a round pen and a squared off area nice and flat for people to practice in as well.
The one thing above all that I found is the downfall of boarding is not having a contract with very specific writing about what is expected of you owner and them as the boarder. Also if you become to friendly with the boarders and they begin to look on you as their friend they almost always need at least once or twice a lenient attitude about something, when you have a few boarders that can start to add up.
Good luck. I hope it works out for you.