I’ve recently undertaken to paint 3 units, two 2 bedrooms and one 1 bedroom.

A 4 bedroom would have you competing with larger condos or townhouses with pools, a much lower rate of return. 

Hello BP Community,I am designing contemporary mountain 2 bedroom / 2 bath cabin in Ohio with a lot of tourists interest year round and four season weather.Here's some amenities that are going to be in the cabin:hot tub on 2nd floor with walk out from each bedroom;wood burning fire place in great room;nice fire pit outside;debating: is putting soaking tub with electric fireplace will be a good investment?

Buying a large new build home can also work well as a house hack as you can charge a premium rent, and generally most bedrooms built now a days have en suites (at least in my market).  

I have a 5 bedroom 2 bathroom house.

Almost nobody that wants a 3-bedroom has only one car, except the occasional single parent with small children, or solo professional that wants a home office and guest bedroom. 

The first unit is a four-bedroom, three-bathroom duplex, while the second unit is a two-bedroom duplex.

Where are the three bedrooms?

It was in a over the garage office/bedroom that never got used.

Being the military, it had that definite institutional overtone to it, but the basic premise was the same.I recently toured a new senior's complex in which on end - for those who were still relatively self sufficient - had individual units (bedroom, sitting room / kitchenette ... effectively a bachelor apartment but without a full kitchen) clustered together in groups of 4 with their own common room / kitchen and courtyard.On the other side of the complex were units for those who required more assisted living.