I lend in the 2nd lien position frequently, but my LTV is capped at 70%. 

The DSCR thresholds can knock your LTV down as well.  5+ opens loan options for 5/10yr Treasury backed notes, 5/10yr SWAPs backed notes with balloons, vanilla 30yr fixed, ARMs, Interest Only, etc... there are a variety of loan options out there.Then you have unicorns lenders... those that will do no DSCR requirements if your property meets the right conditions. 

You can learn a whole lot from a variety of great podcasts, including the BP Podcast, @Whitney Sewell's The Real Estate Syndication Show, @Brandon Turner's books on multifamily and much more.

My current situation will not allow me to move frequently but we make a good income.

This is a great question, and as a military spouse I see it asked really frequently.  

Do you frequent auctions?

There is a vast variety of homes you can invest in from under $100k with great a great return to expensive luxury homes you might be able to flip and get a good deal.

The longer you allow this tenant to stay and keep missing payments, the worse the situation will become (and the more money you will lose).There are a  variety of ways to get rid of a tenant (eviction is one, but it's time consuming and can cost a lot, and you need to follow the law and local regulations). 

This is such a great question and gets asked frequently. 

I agree that 20% it pretty much the lowest you should go for an investment purchase, but luckily there are a wide variety of other options when purchasing a primary.