I consulted http://www.merriam-webster.com/dictionary/cast%20about and http://www.oxforddictionaries.com/definition/english/cast-about-or-around-or-round?q=cast+about but still don't understand why there's an indirect object pronoun after cast about? Can her be omitted?
Source: Joanna Trollope, Britannia’s Daughters, The Cresset Library, 1988
Miss Rye ran a highly successful law-copying office for women clerks in Lincoln’s Inn Fields, and because she was besieged by the demands of educated women for work, she had cast about her for an alternative and suitable occupation and had come up with the idea of emigration. There was a rising demand in Australia, New Zealand and Natal for superior servants and for governesses and Miss Rye felt that the women who begged her for employment would be ideally suited...
Afterword: I thought to mention that answerer CopperKettle linked to a PDF on dependent prepositions patterns, which doesn't contain cast about, but am I right that the same phenomenon applies here?