We started a horse retirement facility in '09 and it is working out well, building slowly with wonderful horses and owners. Some horses have come quite a distance - it all depends what the owners are looking for. I *highly* recommend doing a business plan, including financials. It isn't just the document, it's the process of making it a complete document that benefits us. I made a lot of changes to my plans as I made our business plan. I treat it as a living document and I check the cash flow spreadsheet frequently (especially this year with the cost of shavings and hay increasing so dramatically).
I would be happy to share thoughts with you - including our business plan if you are interested.