Botswana is considered relatively safe for solo female travelers. Crime rates are much lower compared to other regional countries and the locals are friendly and helpful. However, as with any travel, some precautions such as avoiding walking alone at night and being aware of personal belongings are necessary.
I traveled all over Botswana as a solo woman. It's a very safe country. Public transportation is somewhat scarce, but it's doable as long as you don't want to stray too far from the main roads.