The tiny “prison window” is in the bathroom. On either side are bedrooms and the only wall for a bed. Considering adding 2 windows on either side of the existing window but seems like a lot of money for exterior appeal? All rooms get a lot of natural light already.

How much work are you willing to do? Are you just after a quick fix like painting and a few adjustments, or are you prepared to, for example, add windows on the wall with a single-window or put up walls around where the cars are parked?

Can you please upload pictures of those two bedrooms?

+1. More glass on the water facing side.