Q.Curing Potatoes
I can find a spot in my house in the fall at 65’F but retaining 95% humidity at this temp seems difficult (unless I’m not understanding correctly). How important is the humidity? Do you have any suggested places?

In most modern homes the basement or garage will work the best for curing the potatoes.
Here are some links for you.
https://www.gardeningknowhow.com/edible/vegetables/potato/storing-garden-potatoes.htm
http://extension.oregonstate.edu/gardening/tips-keeping-harvested-potatoes-fresh