In this blog, I'm recommending four particular road biking rides to get your legs warmed up, starting with a couple of easy rides and working up from there. All of them are less than 30 miles. The road cycling guide has more than 30 rides overall, and almost all of them, with the exception of the Ride to Bogus, are snow-free.
Start from Municipal Park in east Boise, near Idaho Fish and Game headquarters on Walnut Street. Go east on the Greenbelt 4.2 miles. Turn right and take the path to Barber Park. Follow the paved path to the left of the park entrance and follow that through a number of neighborhoods for several miles. Ride on the detached pathway along ParkCenter Blvd., turn right on River Run Driver, follow the bike lane to the paved Greenbelt access and ride to Broadway bridge. Cross the river at Broadway, turn right, and return to Municipal Park.