A loop around Pittsburgh that doesn't follow the major rivers, doable in one day. I've biked this twice, with friends. On a hot day (80s) it took 10 hours, on a cooler day (70s) it took 9. I tend to stop and take pictures a lot. If you're not the type that stops much, it could be done twice as fast. My advice: do this ride on a cool day. McKees Rocks has some nice old churches. Glass Run Rd was a fun downhill (good asphalt).