This site has some info:
https://www.visitnh.gov/things-to-do/scenic-drives
In my area, I like West Road in Hampstead, NH. It’s winding and hilly and fun. Lightly policed
Not a long drive but other roads in the area are good too.
The coastal road that starts in Seabrook and ends in Portsmouth is something you should check out at least once as well.
There’s a dope route that goes from Hudson to Windham, but I can’t remember the name. Basically the beginnings and ends are the DCU in Hudson and Windham High School.
Can’t wait til it’s Miata weather again. Or til I score my Camaro.