Have both homes completed and sold in less than a year.. and then are taking a much needed break from construction:)Any advice or ideas would so appreaciated!

This is the best way to get good at analyzing deals and will allow you to quickly have a good idea about how a deal will work.

The idea of “giving back” by providing the kind of experience you’ve appreciated as a traveler is such a fantastic approach and will definitely resonate with renters, especially healthcare professionals.Single-family homes and cabins sound like a perfect fit for what you’re envisioning.

I just don't like the idea of single member LLC because then what if something God forbids happens to one of us or when we have a family how do we ensure that this is legally theirs?

Thanks for sharing, the POA to access the original docs is a great idea, and I'm totally stealing it for the future. 

The umbrella is a good idea as they are usually not too expensive for the amount of coverage.Get a good STR policy.

Perhaps your #6 of repurposing commercial in to multiple small residential units is the best idea I can see in SA as it has had way too many Single Family rental homes added the last few years. 

Would it be a bad idea to buy a single family home built in mid 1930's?

Why would anyone start the purchase of a property, having zero idea if they can actually execute their business plan? 

Yes, one approach is to continue with finding other cash flowing property.Let me suggest some other ideas for you to ponder, especially since you've also mentioned you are looking hard at DST's:What about Opportunity Zone funds?