Holbrook is generally a safe place to travel solo as a female. Crime rates are relatively low compared to other cities of its size. Of course, as with any travel, it is always recommended to be vigilant and aware of your surroundings, ensuring you stay in well-populated areas and avoid shady or overly isolated areas at night. Additionally, it's always sensible to keep your belongings secured and not attract unnecessary attention. Respect the local culture and customs, and you should have a safe and comfortable journey. It's a friendly city with great tourist attractions as well.