I'm using Cuentos de Ensalada with my Spanish 1 classes in the present tense and with my Spanish 2 class in the past tenses. In one episode, they learn the teacher's schedule, when she wakes up, when she drives to school, when she exercises, etc.
To review the previous episode, I put the sketches on the board and asked the students to tell me about her schedule. When we got to the sketch of her driving, a girl raised her hand and correctly used "condujo" without hesitation. I was so glad to see that even the irregular verbs didn't pose a problem for the Spanish 2 students.
That evening, I took home writings from the students in which they wrote several diary entries as if they were "Brandon" from the book "El Nuevo Houdini". When I read their writings on the diary entries, my excitement from earlier in the day diminished. Either the students didn't take into consideration that since they were writing as if they were Brandon they needed to change the verbs accordingly (from él form to yo form) or we had a LOT of work to do with the first person singular form of verbs in the past. The diary writing assignment was on a day that I was out sick so I didn't specifically leave a reminder that they needed to change the verbs, so that may have helped them, but that I'll never know.
What I do know, is that when they produce answers, as they did during the exercise in class, it's not as a result of memorizing or "studying" but the result of constant input, input, input. Of which...obviously... they need more.