"Teach Yourself Esperanto" and "Step by Step" could be a little boring, because they are very detailed. Reading either one from end to end, will give you a very good knowledge of Esperanto.

I do not recommend to mix courses. Stick to one course and complete it. If you need variation, watch the videos, but keep studying the original course.

Most people find "Gerda Malaperis" an interesting book. Some don't. The whole text and the audiobook are available on the web:

http://esperantofre.com/eroj/ilo01a.htm#inter

Videos at

http://esperantofre.com/edu/kino01a.htm

http://esperantofre.com/edu/kino02e.htm

Enrique