I live in Phoenix and my business partner and I put on a couple local forums for investors like yourself to network.

Having the seller carry a second is not a problem for the first, as long as their business with you is finished and the loan has closed.

It's a business - acquiring/building, managing, and growing a business. 

I think you just have to work it in as the cost of doing business. 

I have found enough business and made enough money not to need to expand outside of this market.Section 8 is a whole different ball game but I find the program is unique in that it's a 3-party relationship adding the variable of a government agency.

Quote from @Matthew Cook: Dig into those comps with a realtor doing business in that market.

PMs are busy - if you email a PM and say "Hey PM, I'm looking at 123 Main St. and I think it will rent for $1500 a month, does that sounds right?"

You are starting a business. 

I figure this would be really helpful for anyone in our business.

The best way to grow your business is to help people and give solid advice in the forums.