Westward to Home and A Perfect Place, Joshua's Oregon Trail Diaries (1 and 2), by Patricia Hermes
I just finished reading Book 2 with 8-year-old Kieran. We are going to visit the Oregon Trail Interpretive Center in Baker City over spring break, and I wanted Kieran to have some historical context for the museum. I had tried to interest him in Little House on the Prairie, but either he was too young at the time or he was better able to relate to the male narrator. (Or perhaps it was the idea of traveling to Oregon that interested him.)
These books are very easy to read--he could have easily read them himself but instead I read to him while he was in bed. They depict the trail and homesteading from the perspective of a 10-year-old boy.
The books served their purpose: I know that Kieran will be able to relate more to what we see at the interpretive center...and 5-year-old Nicholas, too!