Her travel history could have been a factor.. If she has never left Thailand is harder. Try to get to Australia or Europe (I hear Schengen is easier to get via Portugal/Greece) before your next attempt.
One consideration is a land border crossing as prior to the new 60 day visa there seemed to be some separation between air/land entries. Also, a less travelled border crossing would be Langkawai Island Malaysia via Ferry to Satun Thailand...then from there to Hat Yai and beyond. I had a good experience with this a few years ago.