No carpet on the basement (humidity will ruin it for you or the future buyer).Look for a good Epoxy Paint.

We too have occasionally loaned out a humidifier to help get a tenant's humidity down.  

I look at the weeks and view what they already have booked in a month and season to gage demand.Also- down south their winter is our summer and there are distinct weather patterns -ie rainy season-hot humid months etc. to plan your pricing and busy times.

I wire the bath fan to a humidity sensor fan switch.

There is so much humidity and wet wood and old trees that there are roaches.

It is a simple device that measures motion, temperature, light, sound and humidity.

Window Kit 112-in x 84-in Clear Heat-control Window Film https://www.lowes.com/pd/3M-Wi...If that doesn’t work, you could try lowering interior humidity (unlikely to make significant difference) or upgrading the windows. 

Cleveland, Detroit, Duluth and the whole upper Mid West have access to fresh water and won't have the same humidity heat events as the growing SE US. 

I think humidity sensing bath fans may be a good investment.

I have seen two different builders say they do not install dehumidifiers and what they put in instead is a fan in the wall that will kick on when the humidity gets to a certain level.