Gave her the template, envelopes, and stamps.

The beauty of sending a letter to the property address is that they will often get forwarded to the current owner's property address, not always but enough to be worth a stamp.

I don't have the time to hand write, stamp, stuff 1500+notices a month.

Liquidity is far easier with a single family home than a multi unit building so if you find out you are not into being a landlord you would be much less likely to lose your shirt.

You state that buy and hold rental investors also lost their shirt?

That's why you can make a killing in real estate, or lose your shirt. :) If there were a perfect system to figure everything out then the gains would be next to nothing.

A seller in the business of Seller finance, finds a firm that stamps the loan, how will they judge the integrity of said originator?

Cost is gas and stamps. 

You will lose your shirt as many other out-of-towners have.I get calls weekly from people in New York who couldn't believe or resist buying properties for $5,000 to $10,000 or even $40,000.

We'll just have to wait and see.Just for fun;I remember in 2000 when everyone was saying the market was hot.I remember when I bought my first house in 2003, and everyone said the market was really hot.I remember in 2005 when everyone said the market was to hot, but no end in sight.I remember in 2007 when everyone said the market was crazy hot, but don't worry it was going reach new hights.I remember in 2009 when everyone lost their shorts, shirts, and rowing paddles as the market crashed.I remember, selling all my real estate in 2005, because everyone else wanted in.