Originally Posted by StephenH

Check into the rides and routes out of Richardson Bike Mart and those used by Plano Bicycling Association; also Greater Dallas Bicyclists. I've heard good things about the Shawnee Trail Cycling Club in Frisco, but haven't actually ridden with them.
I'm on the south side of Garland. The local Greater Dallas Bicyclists routes start at Poteet High School in Mesquite, and go down into Sunnyvale. I ride up into Richardson some. If you pick the right route, traffic isn't too bad, but you can hit some long or non-changing lights, too.
Some of the bike trails work pretty well, some are a little too crowded (Katy Trail) or have at-grade intersections.
One reason the routes down White Rock Creek and around White Rock Lake are popular is that you seldom have to stop at intersections. There are places where it's better to use the roads when going around the lake, due to pedestrian traffic or rough trails.