On the Fly by Nicky James

Everything is changing.

When her core group of freight-hopping friends start settling down, Willow is left adrift and all alone to ride the rails.
She can’t quit like everyone else. For eight years she’s been on a quest for answers about her past, and LA is where she suspects she’ll find them.
With a serial killer still loose on the rails and no one else to ride with, Willow’s lifelong best friend, Billie, insists on coming along.
Riding with Billie is a dream come true. They know each other inside and out, and Billie’s presence in Willow’s life has always kept her grounded.
But Billie has always had strong feelings for Willow that go beyond friendship, and Willow has always insisted on keeping things the way they are.
Why mess with a good thing and risk losing the one person who keeps Willow grounded?
Can Billie prove to Willow that she will be there no matter what, that she will never let go no matter how bad things get?
As secrets from Willow’s past unfold, their relationship is tested and hard choices must be made, but sometimes the only way to move forward is to make a decision on the fly.