You can get a feel for what type of person they are and perhaps they'll feel more accountable knowing you are a real person and not just an email account or voice on the phone.  

Also mix your voices up i.e yellow letter, postcard, etc.

Has anyone found a single go-to source that provides a nice outline of how to get started:Where to find/purchase listsWhere to find best mailer options - yellow letters, etc.What phone services to use - google voice, etc.Scripts for responses/screening callsScripts/process for initial homeowner interviewsStrategies to offer homeowner/seller options - cash buy vs. wholesale vs. subject to vs.

so I will devils advocate... we are assuming OP is going to be the voice of reason.... and silent partner wants to buy a gold plated toilet... what if OP is the one chasing an episode of fixer upper...? 

Don,Install a duplex outlet using RG6 (cable tv) and a Catagory 5 twisted pair cable (voice/data) to each location.

Great advise/comments so far, thanks.So the situation has now slightly changed and would hope to get more advice…As I mentioned above it looks like the tenants are moving out however this has not been confirmed by them as I am unable to reach either of the tenants (A or B) ones voice mail (A) says that her phone is broke and she is replying to messages as she can, the other (B , who moved already moved out) I suspect does not care does not ansure.

Dropped my first 45 letters in the mail on Tuesday and when I got out of work today and checked my google voice account I had voicemails from 3 different people already!

Here I had an elderly lady who could stand before a judge and in little squeaky voice say, no, I didn't understand it that way at all.

If I don't want to accept such calls into MY home, I wouldn't answer it, that's why voice mail was invented. :) 

If I call you and tell you in a mono tone voice, "Yeah, I'll sell you my house.