Seems my problem is the long chain run between the crank and hub. I have a nexus 7 speed hub rather than a cluster, and when going over rough (usually dirt path with ruts from when it was muddy) the chain will hop from the top of the rear sprocket when I cease pedaling (putting pressure on the chain). Would something like the KORE chain tensioner mounted upside down and putting pressure on the top run of chain cause any other problems like with the front derailer and shifting, etc.