I do screen heavily, but fear that with less expensive properties it will be difficult to find "quality" applicants that can pass screening unless I greatly lower standards.  

I would suggest you screen this person as a new tenant and see if he qualifies.

Looking to start investing as a way to generate semi-passive income in order to increase my quality of life and spend some more time with my family. 

Crosby, worth touching base with an attorney because tenant law can be so local, but that being said:You have the right to screen and approve the people that live in your property (adults anyway).

So you screen them to find out as much as you can and make an informed choice.

I definitely have a lot of those qualities in me and getting better everyday.

Does anyone have advice on the best times to begin advertising, examples of leases in similar situations, and best practices for screening tenant-roomates? 

The return on equity is low and damage too costly if you don't screen well.If a nicer place I would explore selling it and taking the (probably mostly) tax-free gain and invest or otherwise use the proceeds for their benefit.As Ashish points out, heirs would inherit the house at it's current value at death whether it's a rental or not. 

Are their listings detailed with good quality photos?

She also has many of the qualities we need to be successful.