Difficult to rent out unit with only one bathroom on lower level?

[Tee Ward]

I'm having second thoughts on a property I was ready to make an offer on.  It's a 2 unit property. The basement of the property can only be accessed through the lower unit which is 1 bed/1 bath.   The upper unit is 3 bed/1 bath on two levels. Two bedrooms on the top floor, and 1 bed and bath on the main level off the living area.  I planned to live in the 3/1 for a few years, do some upgrades, and then eventually rent it out. 

Initially I didn't think much of the bathroom being downstairs.  I grew up in a house with the same layout and I come from a large family. It was the norm for us for many years.   I ran the scenario past a few friends and they all said they would prefer a bathroom upstairs near the bedrooms and they probably would not be interested in renting it for that reason, especially at the rate I hope to rent it out for.  One of my friends thinks the set up will seriously limit the pool of potential renters and the amount of rent I can get. 

The bedrooms upstairs are on the smaller side.  I thought of adding a half bath in one of the bedrooms.  However, the bedrooms do not appear to be over plumbing below so that might be very expensive. 

Any thoughts or advice on this scenario?