I haven't found an answer to this specific question on BP or elsewhere online: if I die, and my SDIRA that holds investment property goes to my adult child, what are his/her options? 

I looked online and it looks like you can email them with stories but from experience I've found it's better to talk to someone who knows them already. 

I am interested in recommendations for online courses or books (or other sources of information) that people have found useful. 

There are some crime maps available online too.

We do cold calls, online marketing and sometimes even door knocking to find motivated sellers.

I would not go online to get medical or legal advice from randoms. 

I just use an online platform to collect rents automatically. 

Here's where to look for them:Real Estate Investment Groups and Forums: Participate in social media and online forums devoted to investing in real estate in Houston and its surrounding areas.

Do a search online, make some calls, choose one, and prepare for the long fight.

Try alternative ways of contacting them like finding out who owns the property, going to meetups, or seeing if they're any online groups for airbnb owners in your area, like an FB group or something.