House in neigborhoood sitting vacant

[Ian Love]

I recently noticed that the house across the street from my home has been sitting vacant for going on a couple months. I did a little research on the property and found that the owner has owned the home since 1983 and only owes about $80k on the property. Based on comps in the area and a quick look on Zillow, it is worth around $300-$320k. I had my agent try and find me a mailing address that I could send a letter to, but the only address listed for them is the home sitting vacant. I would like to get in touch with the owner somehow and am planning on dropping a letter in their mailbox this week letting them know I would love to buy the property, but am not sure exactly how to phrase the letter. Does anyone have any suggestions on how I can give myself the best possible opportunity to make a deal here? I was thinking of making a cash offer up in the letter for closer to $200K, but not sure if I should hold off on the specifics until I have spoken to them more. Thanks!