Hi there! I used the dokodemo no doraemon book for a semester last year, and I've got to say it sucks. It's full of simple exercises but does not provide grammatical explanations, and is best thought of as "a work book that is missing the textbook." Frequently I was slammed with a page of moonspeak and I was left wondering why I was learning the obscure vocabulary for two reasons:
1) Most of the vocabulary was useless, like chapter 3's titilar "世界温暖化" (Global Warming), or the recycling/broadcasting chapters. I have no interest in learning these deep words when I still don't know how to read the signs above the immigrations desk at the airport! I also wanted to learn intermediate grammar, but I learned nothing new from earlier levels, because I was instead learning the kanji for "Carbon-diozide" (which you'll forgive me for forgetting--who cares?! I'll look it up in a dictionary if I ever encounter it!)
2)Vocabularly from one chapter is not used in future chapters.) This makes every chapter a totally new drill, with previous chapter's work fading from lack of review. Unless you have a good teacher, (and not the kind who leaves you to learn on your own), you're not going to learn much from this book. This book might be acceptable for self-study, (albeit not that good), but it's horribly inept for the classroom.
So while I'm not sure what book to recommend for intermediate students, I'm warning you not to waste your time on this one! Even if it's rather cheap to buy...