The Yellow Trail is a forest road that acts as a shortcut bypassing the west end of the Blue Trail (North)
and isntead heads directly to the Etowah River crossing opposite the Blue Trail (South)
. The bypassed section to the west is quite enjoyable though, so it would be a shame to skip it!
The North and South sections of the Blue Trail are separated by the Etowah River. And while it's possible to forge, it can be above waist high with fast currents. So wisdom suggests you wait for a warm day after a dry spell to try it.
If you're not feeling up to the river crossing, the Yellow Trail can be used as part of a lollipop loop on the return when riding the Blue Trail (North)