It´s a small amount and going back and forth with a tenant on something like that, insinuating they have to pay because they are too dumb to figure stuff out could create bad blood over nothing.

Call them from a cell phone so you can take a picture showing the date/time/length of call.  

Not one of them has ever said it was a bad decision buying their property I would say all of them would probably say it was the best thing they've ever done.Here's my plan take from it what you will (I wish my parents knew enough to do this).I have two kids and soon as they turn 18 I will have them buy a 4-unit using FHA 3.5% down and a blood relative (me) as a non-occupying co-borrower and source for down payment.

They can be a pain in the *** at times, but they've improved a lot since January when they started.Feel free to give me a call, the number on my tag line is my cell. 

If real estate is truly in your blood I would highly recommend obtaining a sales type position either as a Realtor or as a mortgage broker.  

We're in a small town where I know all the contractors personally, have their cell phones, know their family, and usually know their home address, so my risk level is pretty low.

Excel also has all those same financial formulas, and the advantage is you can reference cells and pick multiple options to see what happens as you shift the variables around.Based on the info you provided and assuming a fully amortizing 30 year loan you'd be paying about 2.7% on a 200K loan...sounds pretty low to me for a SF deal, but I guess it's possible.

Call all those people in your cell phone. 

Unless you have a CDMA cell phone (Verizon and Spint), you can request the roaming and get the calls yourself.

Cold call me after 7pm and you are likely to hear words that will give a sailer PTSD. 8 am is ok but I don't call anyone for business until after 9am on a cell or home phone if I don't know them or their schedule.