HUMBOLDT COUNTY — Standing next to Lt. Gov. Gavin Newsom on a hill overlooking southern Humboldt County, a second-generation cannabis farmer pointed to the valley below. “There’s one,” he said, gesturing at a clearing in the trees. “And there. And over there. They’re all over.” Newsom and Rep. Jared Huffman, D-San Rafael, nodded as they gazed at marijuana grow operations below, taking it all in. They were in the middle of what had been billed a “Cannabis Fact Finding Tour” — a new rite of passage for California politicians grappling with questions of legalization.