Several songs could connect with Of Mice and Men in many ways.
One specific example might be George and Lennie's dream of owning their own farm and "livin' off the fatta the land." This is an expression of the American dream and to this any number of songs might connect. Among them:
- "American Dream" by Crosby, Stills, Nash, and Young
- "California Sky" by the Bastard Sons of Johnny Cash
- "Castles Made of Sand" by Jimi Hendrix
- "One Friend" by Dan Seals
- "Rusty Old American Dream" by David Wilcox
- "Shot Full of Holes" by Jason Boland and the Stragglers
I'm sure other responders can offer you additional possibilities as well. With these song lyrics in mind, it would quite easy to review the passages of the novella where George and Lennie discuss thier plans to buy their own farm, particularly relevant might be the passage when Candy joins George and Lennie's plan and they realize the buying of the farm might be much closer to becoming a reality than they once believed.