One wire alternator.

You don't need "another big wire" to the rear if you use a double pole (4 terminal) switch. Just run a pair of no 14's up front.

If you are running MSD, which powers up/ down with a low current "enabling" wire (the small red) all you need is to:

Feed your ignition switch, through a fuse (say 5A) to one of the no 14's going back. Where the other comes back up, run that to your MSD "small red."

If you are running an ignition other than MSD, which requires more switched current, just take the no 14 coming back up front and use it to "key" a Bosch style relay and use that to switch your ignition.