@Phillip Austin I self-manage my properties including some where I do rent by room as a primary strategy, and it is very effective if done well with good screening in place.The difference is starting with shorter leases for me. 

But if your looking to cash flow like $500 or more per month you might want to look into more cost effective markets where you can purchase a property very cheap and the rents will give you that type of cash flow your looking for.

Also, your total returns go down without any leverage because you lose the multiplier effect of appreciation.Now, to answer your question.

Alternatively, umbrella insurance may offer cost-effective protection.

Most come out ahead over an extended period of time by buying better quality assets where they perhaps have to leave some capital in the property but find themselves able to sell for real gains or refinance out appreciated equity and scale more effectively that way. 

In your opinion, what is the most effective way to establish an LLC? 

All these will effect long term appreciation and rents.  

Any tips on targeted marketing, effective lead generation, or even some "outside-the-box" tactics?

Start small, network with other investors, and use tools like BiggerPockets calculators to analyze deals effectively.

Then you add the compounding effect of hurricane Dorian and it was crickets.