Longest loop is maybe 1.5 miles, but you can vary it to keep the scenery interesting. A couple of short but relatively steep climbs good for pushing your legs, with a few spots of sand or mud that can sneak up on you if you're not paying attention. Very little technical stuff. Usually pretty low traffic on this trail, more often people walking than riding their bikes. Good for XC training, for getting to know a new bike, or for exposing a non-mtn.
Any route is fun but see below for the best.
Take it and veer right about half way up the hill. Then just keep going around and you will find some singletrack to the right or keep going straight to shorten your trip. The other directions are confusing. Here's the beef. On the right you will see a sign for Battle Creek Trails and a parking lot.