I am not an attorney, but at a minimum, you're going to need (1) adequate property insurance, (2) a standard lease agreement, (3) a method for vetting tenants/doing background checks, (4) a method for collection of rent, and (5) possibly a license for the property to be operated as a rental (you will have to check the requirements in your jurisdiction).

In most cases, if someone discovers you're serious about taking this through the court system, they'll try to get things resolved without having something on their background.

You'll want to search for a 'How Much House Can I Afford' calculator in lieu of a standard mortgage calculator.

I've been looking at growth rates, etc of towns but am wondering if there's a trick to discovering that next hot market (besides foreseeing the future). 

Several mid-range builders have started included it as a standard option, so it's becoming more of a norm in that 250k+ price range. 

So old and fallen apart, there are a couple of occupants in the two buildings living off the government paycheck, but it's definitely not going to pass any minimum standard conditions if ever thought of section 8 ....

Banks require 3-12 months of reserves per property and most will allow you to use a certain percentage of retirement accounts (75% seems pretty standard) to count towards reserves.

Notify your tenant that they will be responsible for all maintenance bills if you discover their failure to maintain was the cause of the maintenance issue.

I know it happens, but does anyone do this as a standard practice, or do you just move on and focus on the next lead?

@Ryshawn Cousar Yes, that is standard practice when renting a lot in a mobile home park for a mobile home that you own.