In my market and markets around me you can get a high quality rental for 150-300k.Rentals aren't feasible for everyone especially if you're in a market that's super expensive and not a seasoned real estate investor this is what leads people to invest out of state passively. 

Those little upgrades can make a big difference in attracting quality tenants.

Some owners don't want to put out tens of thousands more to outfit a high quality STR. 

Today the real need is quality lead lists of actual motivated, stressed sellers!!!!!!!   

If you charge below market rate, you will attract low-quality renters who are more likely to trash the property and make your life miserable.

For example, adding a bathroom can increase your home's value by 10-20%, depending on the quality and type of bathroom.

The noise from upstairs is annoying so next time I'd do more testing of the quality of soundproofing in the ceiling (older home so wasn't as good).

The rent is similar, but with much higher quality tenants and less vacancy risk.

And, I plan to follow a strategy that includes buying higher quality, rather than just looking for high cash flow. 

Poor insulation and single pane windows will raise that cost to run the furnace quite a bit so you might want to see where the break point is for upgrading.The biggest issue is power outages in the winter.