If they want, they can leave one side of the Arena bumped up all year (I would prefer natural bumps, though, not those huge crappy mounds that they ran the bump contest on). That would create a good lap for the jibbers, with a run through the terrain park on Wild Air, then straight into a nice zipper line on Arena (maybe with a permanent kicker on the bottom of the bumps).
Since this is probably not going to happen (too much stuff going on on that trail between Snow Mountain Biking, Rail Jams, etc.), I nominate the part of Open Pit after Upper Darby cuts through for an easier (and shorter) bump run.
The problem (and the cool part) with Gore is that the trails are kind of narrow, so a half and half trail would be hard to come by (only Arena springs to mind).