When you say hoop house - are you talking unheated - if yes - This is a great book. I heard her speak at the Mother Earth News Conference in 7 Springs PA this summer. SHe uses cold frame and various covering to grow fall veg crops through out thw winter.
Kale, some lettuce and radishes, etc After reading this book there were many more than I thought.

Here is a link that might be useful: book

All root crops.

Why not try some kohlrabi
here's a pic of what I planted last august and still growing slowly, maybe once it warms up I'll have something.