RefTeX has the usual general keymap, load hook and mode hook.
The keymap for RefTeX mode.
Normal hook which is being run when loading reftex.el.
Normal hook which is being run when turning on RefTeX mode.
Furthermore, the four modes used for referencing labels, creating citations, the table of contents buffer and the phrases buffer have their own keymaps and mode hooks. See the respective sections. There are many more hooks which are described in the relevant sections about options for a specific part of RefTeX.