but I can't find where the wire from the alternator splits off to feed everything else. I know it splits before the Alt guage, but I don't know where. Any ideas would help, thanks.
That's the limitation of the factory setup, IT DOESN'T!!! The primary wire runs from the alternator through the firewall connector to the amp gauge and then begins to split up to the battery (starter relay), ignition switch and headlight switch. The bulkhead connector was barely adequate for the stock loads when new, and after 40 years of dirt and corrosion, they get problematic (catch fire) if you route heavier loads through them.
As I suggested above, an "axillary distribution/relay box" can be added for fans, lights, stereo, etc... Another good mod is to run a 10 AWG wire from the alternator directly to the battery (use a fuse link to protect). This will divert the main charging load from the bulkhead connector and AMP gauge. The AMP gauge will no longer indicate much, but it and the bulkhead connector will be far less prone to overheating and melting down due to increased load.