I also don't know how realistic it is that we'd be able to cover the mortgage if we moved back into the property while semi-retired.I feel like the right answer is selling the CA duplex, but again, it's killing me.Thoughts?

For Baltimore City, the General Residential Districts say:R-5 also allows for single-family semi-detached (14.5 units per acre), single-family attached townhouses(17.4 per acre) and multi-family housing (17.4 per acre).

I do know of some off market ones you could get on the semi cheap.

@Christian BowenIf you’re looking out of state, start with places that you have friends or family or would otherwise want to take semi-regular trips to.

The narrow property is semi-ideal to build an ADU with posterior access to a cul-de-sac.

As long as you're doing yearly or semi-yearly walkthroughs to ensure there's nothing too bad going on, the security deposit should cover whatever is needed. 

The property is in Northwest Arkansas so we get very hot summers, very cold winters, and semi-frequent tornados and hail storms, so roofs usually don't last longer than 15 years around here (according to the roofer). 

I have some experience being a semi-landlord in Seattle, renting out the other rooms in the house I've been renting.

We live in a 5 bed 2 bath semi-detached twin near the Schuylkill River trail and purchased the place at $101,000.

Here's the Fannie selling guide which says unit count can be 1-4 unit, and then separately says dwelling type can be attached, detached or semi detached.