Trunk Mount Battery - Wire Routing

One more question on this. Did you guys run your neg. cable from the battery lug to the engine block? Or is it acceptable to just run that ground cable to a welded nut on the frame rail under the trunk and another ground cable from the engine to another nut on the front frame rail?
I ran a 00 welding cable to the rear frame rail, and subframe connectors and elephant ears to complete the circuit. Probably ought to add an engine ground.