Kevin Moloney for The New York TimesMelissa Bechhoefer, registrar of the Colorado Historical Society, with a sword and scabbard that belonged to Zebulon Montgomery Pike. Kevin Moloney for The New York TimesIn spiffying up to attract tourism, Pueblo, Colo., settled on the idea of a River Walk to anchor downtown. Much of the attraction, along the Arkansas River, offers themes related to Pike’s Southwestern expedition. PUEBLO, Colo., July 13 — All over tourist country, there’s an invisible borderline where people stop and shut their wallets, as if halted by a sign: nothing beyond here to see. snip... Now Pueblo...