First-novelist Ross breathes fresh spirit into stale formulae in this dandy comic Western, a tale of two orphaned sisters on the Oregon Trail. It's 1846 when Papa Heath dies of a stroke, leaving 12-year-old daughter Emma--the sharp-witted tomboy who narrates this novel--in the care of 17-year-old sister Jessie, whose beauty is equalled only by her religious fervor. Jessie decides they will go to Oregon to convert the Indian; so off they head to Independence, Mo., staging ground for covered-wagon caravans. On the way, they're accosted by a pair of hillbilly would be rapists; after Jessie fights them off, she proclaims that for the trip's duration Emma will masquerade as a boy--the set-up for a slew of misadventures to follow. In Independence, the two hook up with Ross' chief supporting characters, vibrant variations of familiar types: there's grizzled old trapper Mego Cobb, refugee from a dozen John Ford films; ultra-macho trader John Garrett, who sets the girls' hearts a-flutterin'; and jolly wagon-trainer George Donner and his wife (striking a jarring note as the novel's sole real-lifers, leaders of the notorious Donner Party that fell into cannabalism when trapped in a Rockies' winter). On the Trail, Emma befriends Mego while Jessie is romanced by Garrett; all's bright local color, blue sky and rolling prairie, until Crows attack, snatching the two girls. Emma's telling of Crow life is often hilarious, the tale's comic highpoint; but as often, offensively stereotyped (according to this account, Crows spent most of their time lying, arguing, lazing about, and comparing sexual organs). In time, the girls are rescued by Garrett; a few added adventures, including a harrowing Indian massacre, bring them to the expected happy ending with Garrett and Jessie tying the knot, Emma in tow. Ross' main achievement here is Emma's voice, full of pluck and a joy to listen to; through her, Ross manages to teach the old dog of the Western some delightful new tricks. An entertaining pilgrimage, indeed.