If you buy in a good market, appreciation will beat cash flow every time. 

Would you even consider a property in a flood zone in either area?

This is located in a tourist lake/ski town with extremely high demand for lodging.  

I have 30K that I can invest with that's in a SDIRA. 

I think diversity is great in a portfolio but so is scaling the area you are currently doing well in.

I am in a similar boat...A goal I have for 2025 is to pay off a mortgage (my highest interest is 4.5% and I owe $180K on it).

I suppose my question on this is: Is her simple statement (which came in a text, btw) to me of "I'm moving out," enough for me to take this kind of action?

I would say certainly within a month.This is your opportubnity to call in a soils engineer and make sure this does not happen again.

Per CoreLogic, only 1.8% of all mortgaged homes are in a negative equity position, and the average homeowner across the US has $311,000 in equity.If anyone has contradictory data, please share.

They are happy to look further from where they live, in a better rental market, because they do not want to do the management.If this were the case, then as others have said a hybrid of a 2-4 unit might be the best place to start.