When she hiked more than 1,000 miles through California and Oregon wilderness, Cheryl Strayed didn’t expect to end up in Hollywood. The author of “Wild,” opening this week as a film starring Reese Witherspoon, hadn’t planned to write about her three-month solo trip on the Pacific Crest Trail. When she finally did years later (at her husband’s urging), she sent the manuscript to Witherspoon’s camp, knowing the actress was looking for complex female characters to bring to the screen through her new production company.