Generally, it's all 3, but mostly Kanji and Kana. Simply put, Kanji is symbols representing whole words, Gana is japanese words spelled out phonetically, Kana is English words spelled out phonetically, or as close to spelled out as they can be. Names of towns and characters rarely fall into Kanji and as a result are often spelled out in Kana.
If you don't know Kanji, it's often easy enough to just follow the kana.