I have found that I really enjoy riding the back roads in Wisconsin. Roads that cars have long forgotten make for some of the most scenic and tranquil of rides.
We've also become spoiled with riding on paved surfaces. There's nothing like a smooth swath of concrete or asphalt to pave the way. Compared to some of the crushed stone recreation trails, I'll take the speed and ease of a rural road any day.
The Oshkosh Cycling Club has a helpful map of their group rides. Which of course can be ridden any time. Checking for cycling clubs in an area you'd like to ride might help you find some of the more interesting (and safer) places that see local bike traffic.