I would say that not bothering to learn Japanese characters might be one of quick and fun ways to learn Japanese (even though this is somewhat unconventional and a lot of people might disagree with me.) The reason is that a lot of learners of Japanese language get overwhelmed by the number of characters to memorize and just give up. I myself also like to start learning a language with the thinest textbook possible so that I can get the gist of the language first. Then I read it over and over, maybe as many as 6 to 10 times, then, when I get the most of that textbook, buy another one, which is slightly thicker than the first one. This way, we will be able to make many sentences with little grammar and vocabulary. It is also a good idea to speak it when we read the textbook because if we speak, we can train our kinesthetic sense, as well as remember better; when we want to remember, say, someone's phone number, we tend to repeat it in mind to remember it, right? It's the same thing.