Unexceptional Western made slightly exceptional by dint of it being a Walt Disney movie, one featuring fairly intelligent writing, acting, and photography, as well as some excellently and innovatively staged stunt work. Christopher Connelly is thin-voiced but competent in the title role, and Robert Reed stalwart and fine as Captain John C. Fremont, who engages Carson to guide him on an ostensible survey mission from New Mexico to California. Being a Disney movie, there is, of course, a precocious kid…