This final lead guitar solo is based on the chord progression to the song House of the Rising Sun. It uses notes from all the scales presented in the book. It is very common for lead guitarists to use notes from more than one scale when improvising.
When making up your own licks and solos, experiment with all the notes and decide what sounds best to you. This solo is in ) time. If you are not familiar with ) time, see Progressive Guitar Method: Book 1 .