I read somewhere that the average in SF is 50% but not sure how that figure was calculated.

Even if you don't plan on selling anytime soon, your expenses will increase each year so you want to be sure to increase your income as well.All the best to you on your search!

@Brooks ConkleAnd for sure be careful of those where the wrong name is called off. 

This is a great place to learn and to connect with people so take advantage of all the great resources.

If it was me, and knowing what I now know, I would find a market where I can invest in, be boots on the ground, and learn the business.

For sure

So I'm trying to learn everything I can as I search out my path to gaining the needed capital to get this train rolling. 

Not sure on Jacksonville, FL.  

I am not used it myself and understand there is a bit of a learning curve .

The zoning will define the permitted uses (this will tell you if you can have an RV/Boat storage there) and it will define the density (this will tell you how many tiny homes you can add).You'll want to make sure you don't conflict the existing duplex to a new use or mixed use where you might put the existing use out of compliance.