If it were any other time of the year I'd send you down to S. Chelmford to the Thanksgiving Town Forest which hooks up with Great Brook State Farm in Carlisle. There are lots of running paths/trails in the woods there.<br><br>
In Lowell, there's plenty of running paths along the river anywhere from UMass Lowell headed north on either side of the river. There are plenty of loops to be made depending on how long you want to go/which bridge you want to cross.