(Long Days on market) and then using secondary financing for closing and carrying costs.

As a new investor, starting in your local market where you have a better understanding is often advisable.All the methods you mentioned are excellent ways to begin your journey.

Perhaps focus on homes with longer days on market, ones that didn't sell during the initial two weeks because priced too high or needs updates but would still pass a loan appraisal. 

I can't tell what part of the country you are in but I bet there is one where you are...or one in the market you are targeting.  

It is a tough market and the easy money is gone.

If the software is not simplifying your life or making you more accurate, you shouldn't use it.Software does have extremely helpful features like online payments, marketing syndication (click a button and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.

Should I already have a property manager on stand by once I find a market that works for me?

That is a very saturated market for STR so I do think it makes sense that 1/3 is underperforming, but based on taking a loss now, I would probably stay tight and keep going because you have the set up in the area.

I'm located in Cleveland, OH and happy to help out with any questions you might have about the market!

All of the great places to find investment properties like meet ups and BP classifieds and local investors and the MLS will be where you go to market yours.