Jenny Creek is off of the Rollins Pass trail. From Nederland, head down 119 towards Blackhawk. When you get to Rollinsville, take a right (west). The road goes along Boulder Creek for a few miles. The Rollins Pass trail itself starts near the Moffat train tunnel. This time of year there may be a lot of snow up at the top and you may not be able to get to Jenny Creek. It's a nice ride and when clear of snow, most of Rollins Pass doesn't require high clearance or 4x4. Rising Sun used to maintain Jenny Creek, but I don't know if they still do or not...might check on their forum for a trip report.