The lines from the poem express a desire for freedom and open space, emphasizing a longing for wide-open country without restrictions. Therefore, the struggle most likely being described is:
Miners and cowboys felt that their open range way of life would be over once their families arrived and helped establish law and order.
This choice aligns with the theme of wanting to maintain an unrestricted, free lifestyle that is often associated with the experiences of miners and cowboys during the westward expansion, reflecting their concerns about the imposition of law and order on their way of life.