@Cody May the guy is 20 minutes away from you. If I were you, I would go directly visit him and say something like "Hey, I was just passing by and thought I'll stop to say hi. Not sure if you remember, I have been your tenant before, and I am getting into real estate. By the way, you own a lot of properties, right? That's impressive. Hey, why don't we catch up over coffee?".
I don't intend to give you a script, but just an idea.
The point is, with the letter, the best that can happen is he'll contact you, and you have to do the above talking anyways. The worst that can happen if you visit is he'll kick you out (very unlikely right?)
Look Cody, your strength is your passion and willingness to learn. Use that to your advantage. Grammar and written language is not your best strength. This is why I suggest a face to face meeting rather than a letter.
Most importantly, take action! We are waiting to hear from how it went!