What's the best way to replace the Cluster Voltage regulator?

That sounds right to me. I finally found a key in one of my books that explains how everything is labeled and I think I understood it. Check your cluster connection at the Dark Blue wire (also lists a tracer, white?). I can't find a consistent orientation for the pin connector to know if it is at 1 or not, but dark blue seems to be the wire running from the bulkhead to the gages. I think the feed to the fuse comes from bulkhead connector N.