I'm looking for a course where the projected time to read through the text and work through the exercises has been estimated. Ideally it should cover the basics for beginners from A1 to B2.
My students use "Kurso de Esperanto" created by Karlo Pereira from Brazil. Most of them complete all the lessons in less than 20 hours.
La Zagreba Metodo should be faster. It teaches about 500 word-roots, which should be enough to get some fluency. It has sound. You can listen while you read.
A book scanned: (with sound) http://esperantofre.com/zagreb/zagreba.htm It has links to the corresponding interactive lessons.
Interactive. Touch a word to find its meaning: (with sound) http://learn.esperanto.com/en/
I used the approach with Duolingo and Lernu to do a lesson or course everyday, in that way i used like 20 minutes for day but like at school I didn't forgot what I learned. Do a little bit every day is helpful to remember because everyday you use the words. I tried with Kurso4 but was to most fast.