Pooks... If you start at Hillcrest (Park Lane) and 635... from those soccer fields (SW corner)... that path goes all the way to the lake with 2 stops for traffic. Go down the path, around the lake and back... you rack up 24 miles.
Otherwise, don't overlook the local bike rallies that are coming up. You can go to a bike rally and ride roads with other cyclists... but keep your speed... have a SAG if you need it and rest stops every 10 miles.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"