Form some type of corporation or an LLC with whatever an Attorney and/or a CPA to help you decide will do the best for your goals.Something else you should do is to get a pre-qualification letter that says how long you might need to do a loan and the maximum amount of loan.  

Start sending letters as someone is collecting the mail.

I send thousands of letters each month, and the source I use for data is a division of first American Title called Core Logic (or RealQuest).There are obviously many ways to get data, but in my years in this business I have found that Core Logic really is the industry standard for real estate mailer data for all types of real estate.The first thing I like about Core Logic is that the data is usually amazingly fresh, and they even tell you how old it is before pulling it.

We have seller financing at multiple price points/balloon amounts/year terms and a conventional financing option.

Send them a letter telling them you found their house to be apparently vacant.

Do you have an actual Written Approval Letter from the seller's lender yet?

Get a loan pre-qualification letter.  

@Spencer Trotman,You may want to re-think your approach.Why not just drop them a hand-written letter in a hand-written envelope with a 1st Class stamp stating your interest in buying a home in their neighborhood and asking if they know of any that might be for sale?

It's kind of a trial balloon, and I'm not exactly sure how we're doing, but we already owned the place, so it's not that we had much of a choice other than renting or selling.If anyone wants to criticize the deal, I'd be glad to know your opinion.

You'll want to hjave this lined up before you buy, plus yo'll want a pre-approval letter so when and if you find a place you want you can put in an offer imediatley!