I think both of their lives were similar as a result of their social positions-Woody, being a poor “Okie” orphan, and Red a female. I think what made their relationship special was the intimacy created by nights under the stars. Under the cover of darkness, they felt freer to express their feelings, hopes, dreams, and fears. Red recognized that Woody was a safe, sensitive, caring person. She trusted him. And he seemed to respect her, treating her as his equal- not brushing off her dreams or rushing her along.
We know by her “to do” list that Red was thinking about Woody before the trip even started. Her pregnancy and the loss of her film and camera seemed to cause her to think more practically than with her heart. Her options would have been much more limited as a pregnant, unemployed, divorcee in California. Given her health and a baby on the way, Red put the baby’s future well being before her feelings for Woody.
Had Red been able to complete the journey, I don’t think she would have stayed put for long. She had a whole lifetime to live in a much shorter time than most.