Her Believing Heart (The Surveyor's Daughters #1)
Vicki Hunt Budge

Evan has wanted to marry his best friend for years, but he comes from the poorest family in town and Nellie’s family is one of the wealthiest. Evan is determined to work hard for the survey crew. He will do almost anything to help provide for his mother and younger sisters, and he will do whatever it takes to win the hand of the lovely Nellie Gardner.
Will the summer survey be enough time for Nellie to sort through her concerns about Evan? Will the most grueling job on the survey crew allow Evan to earn the respect of the girl he loves?
Author's Promise: This is a clean and wholesome historical western romance with no cliffhangers.