@tinker Not sure how relevant my advice is - I'm in a USDA 10b zone and Northern VA is 7b but potatoes are incredibly easy to grow. Here it takes 8-10 weeks from putting a cutting with an eye (root) in the soil to having a bowlful of crop. Here they can also be grown almost year-round but they grow slowly in the winter. As I warn folks when starting out though, once you start growing potatoes, you never really stop as you will always miss a few tiny ones that will launch new plants. Putting them in a larger bed is hazard for this reason; they are better contained in planter bags or boxes.

A classic standby recommendation when you are starting out and just learning are radishes. They grow quickly, and if they don't, it often tells you there is an issue with the soil, the setting or your initial technique. There are several great recommendations for fall crops in this thread, though it may take you longer to get feedback from those.

Best of luck.

@pmcdonald - Honestly, I love that about potatoes. Like, if this bed grew nothing but potatos, that'd be fine!

But I like your idea about radishes!!! It would be a quick turn around and really get me used to being outside and working in the soil. Then maybe in Spring I plant potatoes and continue doing that.