It turns out this pursuit for pleasure is part of our biology. According to Douglas J. Lisle and Alan Goldhamer (authors of The Pleasure Trap), our unconscious behavior is driven by the Motivational Triad. This means that all animals are after three things:
2) Avoiding pain.
3) Attaining goals using the least amount of effort possible.
That pretty much sums it up, doesn't it? It's the biological version of Maslow's Hierarchy. Take a look at how it fits into our day-to-day writing lives. Besides the food part of our writing life, consider how much joy we get out of living vicariously through our characters. As for avoiding pain, well. Wouldn't you agree that besides being talented writers we are also talented procrastinators? And guess why so many of us LOVE pansting?* Yep. Getting into that sweet writing zone and allowing the story to flow onto the page with minimal plotting helps us reach a quantifiable goal with less effort.
*Don't get me wrong. ANY writing, whether it was plotted first or pansted is still hard work. For me, this is the easiest way to get a story down because the internal editor has been temporarily silenced. But even so, writing is never easy!
The point is, these motivations drive your character, too. She also seeks joy, tries to avoid pain, and wants to accomplish her goal in the laziest way possible. Obviously, there would be no story if you granted your hero these things. Without pain, there is no chance to overcome. Without facing fear, there is no growth. Without spending large amounts of physical and mental energy on a problem, we never discover how strong we really are.
As your character embarks on her journey, remember two things:
1) She's working towards a new environment where life is comfortable, pain is mostly avoidable, and whatever goals she's after are relatively easy to meet.
2) These desires play a role in your hero's internal struggle throughout the story. This is because there is always the temptation to give up. She can accept complete defeat (death), or a blighted existence where meeting the needs of the Motivational Triad are stunted. Pleasure is now about the absence of pain. Avoidance of pain just becomes avoiding intolerable levels of pain. As for spending the least amount of energy.... that rule still applies. It's just that the goals are now stunted in size and grandeur.
The thing is though, the hero is a hero because he or she doesn't give up. Heroes push through the pain and the temptation to give up. Even though they are strong enough to carry on, that wish is still there.
As you plot (or pants!) your story, remember the unconscious biological behaviors that apply to nearly all living things and use them to your favor.