Colter's journey - William W Johnstone

Leaving their Pennsylvania home to forge a new life in the untamed Oregon Territory of 1845, the Colter family is ambushed by a kill crazy gang of Indians on the Oregon Trail. Fifteen-year-old Tim Colter manages to hide--only to return and find his parents butchered, his sisters Nancy and Margaret missing.
Forced to fight for his life, the young Colter embarks on a perilous journey across a lawless frontier, hoping to save his sisters and salvage the dream they lived for. But first, Tim has to figure out how to survive. Luckily, he finds a new friend in Jed Reno, a grizzled one-eyed trapper who's lived in the Rockies since the 1820s. Together, the mountain man and the greenhorn set out after the marauders, blazing a trail of vengeance. With danger at every turn, and death just a heartbeat away, Colter has no choice but to grow up fast--one bullet at a time . ..