When I look for my next property, I work on cleaning up credit, so my scores are as good as I can get them.  

The bank will want you to be working for a certain amount of time and that have certain credit score plus have your financial ratios match what they want. 

We're wondering about various what-if's though, such as what if the people tear up the place, what if we don't want to rent to someone in particular due to references or credit or pets, etc.

I don't accept credit card payments for this very reason.

If your rate is low on the 5 unit, I might consider the possibility of a line of credit for my equity instead of an entire new mortgage.  

I have taken all my taxes and insurance out of escrow, and I run them through credit cards to rack up points, so I pay a lot of bills every year.3.

I called Home Depot, they told me to dispute the credit card charges so I did.  

One of the things you can start doing is reviewing your credit score and work on improving it if needed.

We bought it for $225k with a 3.125% mortgage and 1) are interested in keeping it as our first rental. 2) We are thinking about using some of the equity (maybe $50k or less as a HELOC to combine with existing cash for our next home down payment that we can convert to a HELOAN through our credit union).

Leave credit cards at home in the freezer in a bag filled with water that has frozen over....lolAmazes me how many people fall for these types of programs.When I buy NNN properties either my buyers wanting to own direct and I find the property or whether they are accredited LP investor on my syndication deals they learn with me while they INVEST CAPITAL to own fully themselves or a piece of the deal.